Body fluids harr

A.
CSF is formed by ultrafiltration of plasma throughthe choroid plexus, a tuft of capillaries in the piamater located in the third and fourth ventricles.Endothelia of the choroid plexus vessels andependymal cells lining the ventricles act as a barrierto the passage of proteins, drugs, and metabolites.Glucose in CSF is about 60% of the plasma glucose.Total protein in CSF is only 15-45 mg/dL, whilechloride levels are 10%-15% higher than plasma.Approximately 500 mL of ultrafiltrate are producedper day, the bulk of which is returned to thecirculation via the sagittal sinus. The normal volumeof CSF in adults is 100-160 mL (10-60 mL for small children).

Cerebrospinal fluid (CSF) is formed byultrafiltration of plasma through the:
A.Choroid plexus
B.Sagittal sinus
C.Anterior cerebral lymphatics
D.Arachnoid membrane

A.
Lymphocytes account for 40%-80% of WBCs inadults; monocytes and macrophages for 20%-50%.Neutrophils should be less than 10% of the WBCs.The reference range for WBCs in adults is 0-5/μL.Disease may be present when the WBC count isnormal, if the majority of WBCs are PMNs. In infants,monocytes account for 50%-90% of WBCs, and theupper limit for WBCs is 30/μL. The first aliquot issent to the chemistry department because it maybe contaminated with blood or skin flora.

2.Which statement regarding CSF is true?
A.Normal values for mononuclear cells are higherfor infants than adults
B.Absolute neutrophilia is not significant if the total WBC count is less than 25/μL
C.The first aliquot of CSF should be sent to themicrobiology laboratory
D.Neutrophils compose the majority of WBCs innormal CSF

A
Normal CSF volume in adults is 100-160 mL. Whenvolume is low, an abnormally high difference isobserved between the opening and closing pressure.The difference is normally 10-30 mm H20, afterremoval of 15-20 mL. Low opening pressure iscaused by reduced volume or block above thepuncture site. High opening pressure may result from high CSF volume, CNS hemorrhage, ormalignancy.

3.When collecting CSF, a difference betweenopening and closing fluid pressure greater than100 mm H2O indicates:
A.Low CSF volume
B.Subarachnoid hemorrhage
C.Meningitis
D.Hydrocephalus

C. Xanthochromia is pigmentation of CSF caused bysubarachnoid hemorrhage, high CSF protein, freehemoglobin, or bilirubin. The bilirubin may be caused by hepatic disease, CNS hemorrhage, or priortraumatic tap. In subarachnoid hemorrhage, the fluid will be pink if the RBC count is greater than500/μL. It will turn orange as RBCs lyse in the first few hours, and will turn yellow after about 12 hours.Granulocyte infiltration occurs immediately after asubarachnoid hemorrhage, and disappears after 24 hours. It is followed by an increase in macrophages,showing evidence of erythrophagocytosis thatremains for up to 2 weeks. After subarachnoidhemorrhage, D-dimer is present in CSF, and can beused to distinguish between a traumatic tap andsubarachnoid hemorrhage.

4.Which of the following findings is consistent with a subarachnoid hemorrhage rather than atraumatic tap?
A.Clearing of the fluid as it is aspirated
B.A clear supernatant after centrifugation
C.Xanthochromia
D.Presence of a clot in the sample

C. Pleocytosis refers to an increase in WBCs within the CSF. Bacterial meningitis causes a neutrophilicpleocytosis, viral meningitis a lymphocyticpleocytosis, and tuberculous and fungal meningitis a mixed-cell pleocytosis. Other causes of pleocytosisinclude multiple sclerosis, cerebral hemorrhage orinfarction, and leukemia.

The term used to denote a high WBC count in theCSF is:
A.Empyema
B.Neutrophilia
C.Pleocytosis
D.Hyperglycorrhachia

D Acute bacterial meningitis causes increasedproduction of immunoglobulins in CSF. Glucose levelsare below normal (

8.SITUATION:What is the most likely cause of thefollowing CSF results? CSF glucose 20 mg/dL; CSF protein 200 mg/dL; CSF lactate 50 mg/dL (reference range 5-25 mg/dL)
A.Viral meningitis
B.Viral encephalitis
C.Cryptococcal meningitis
D.Acute bacterial meningitis

D In viral (aseptic) meningitis, the CSF glucose is usuallyabove 40 mg/dL and the total protein is normal orslightly increased. Some types of viral meningitis cancause a low glucose, which makes the differentiationof bacterial and viral meningitis difficult. Low CSFglucose and elevated total protein are also seen inmalignancy, subarachnoid hemorrhage, and somepersons with multiple sclerosis. Low glucose inmalignancy and multiple sclerosis results fromincreased utilization. Glucose is reduced insubarachnoid hemorrhage due to release ofglycolytic enzymes from RBCs. All three conditionsresult in high CSF protein, but multiple sclerosis isassociated with an increased IgG index owing to localproduction of IgG.

9. Which of the following conditions is most oftenassociated with normal CSF glucose and protein?
   A.Multiple sclerosis
   B.Malignancy
   C.Subarachnoid hemorrhage
   D.Viral meningitis

C The total CSF protein is increased in less than half ofpersons with MS. The IgG index is increased in 80% ormore of MS cases. While the IgG index is sensitive, it isincreased in many other disorders. The presence ofoligoclonal banding (two or more discrete bands inthe gamma zone following electrophoresis) is seen in90% of persons with MS, and in few other diseases.While not entirely definitive, it is the single mosteffective laboratory test for the diagnosis of MS.When performing CSF electrophoresis, the serumpattern must be compared to the CSF pattern. Atleast some of the oligoclonal bands must notbefound in the serum pattern for the test to beconsidered positive. Beta-2 microglobulins areincreased in CSF in inflammatory diseases (especiallymalignant diseases).

10. The diagnosis of multiple sclerosis is often basedupon which finding?
    A.The presence of elevated protein and low glucose
    B.A decreased IgG index
    C.The presence of oligoclonal bands byelectrophoresis
    D.An increased level of CSF βmicroglobulin

B In fungal meningitis, the glucose will be low and the total protein elevated; however, unlike bacterialmeningitis, the lactate is usually below 35 mg/dL.Fungal meningitis usually produces a pleocytosis of mixed cellularity consisting of lymphocytes, PMNs, monocytes, and eosinophils. In some cases,lymphocytes predominate; while in others, PMNscomprise the majority of WBCs.

11.Which of the following results is consistent withfungal meningitis?A.Normal CSF glucose
B.Pleocytosis of mixed cellularity
C.Normal CSF protein
D.High CSF lactate

B Amoeba in CSF appear very similar to monocytes in stained films but can be differentiated by theircharacteristic pseudopod mobility in a wet prep on aprewarmed slide. Naegleria fowleriand Acanthamoebaspp. are causative agents of primary amoebicmeningoencephalitis.

In what suspected condition should a wet prepusing a warm slide be examined?
A.Cryptococcal meningitis
B.Amoebic meningoencephalitis
C.Mycobacterium tuberculosisinfection
D.Neurosyphilis

C IgG Index =(CSF IgG ÷ serum IgG)(CSF albumin ÷ serum albumin)
An IgG-albumin index is the ratio of CSF IgG:serumIgG divided by the CSF albumin:serum albumin.Values greater than 0.85 indicate CSF IgG production,as seen in multiple sclerosis; or increased CSFproduction combined with increased permeability, as seen in CNS infections. Multiple sclerosis ischaracterized by the presence of oligoclonal bandingin the CSF in more than 90% of patients with activedisease. The total protein and myelin basic proteinare often increased and the glucose is decreased.Reye's syndrome results in hepatic failure, causinghigh CSF levels of ammonia and glutamine. CSFlactate is usually normal in patients with multiplesclerosis.

Which of the following CSF test results is most commonly increased in patients with multiplesclerosis?
A.Glutamine
B.Lactate
C.IgG index
D.Ammonia

A A relative (percent) increase in PMNs may besignificant even when the WBC count does notexceed the upper limit of normal. For this reason, aWBC differential using a concentrated CSF sample isalways performed on neonates and when the WBCcount is > 5/μL. Cytocentrifugation should be used toconcentrate the cells followed by staining withWright's stain.

Which of the following is an inappropriate procedure for performing routine CSF analysis?
A.A differential is done only if the total WBC count is greater than 10/μL
B.A differential should be done on a stained CSF concentrate
C.A minimum of 30 WBCs should be differentiated
D.A Wright's-stained slide should be examined rather than a chamber differential

C monocytes
In newborns, the upper reference limit (URL) for WBCs is 30/μL (URL for adults is 5/μL) with the majority of WBCs being monocytes or macrophages. In normal neonates, monocytes (including macrophages and histiocytes) account for about 75% of the WBCs ,lymphocytes for about 20%, and PMNs for about 3%.In normal adults, lymphocytes account for about 60%of the WBCs, monocytes for about 35%, and PMNs forabout 2%.

15.Which cell is present in the CSF in greater numbers in newborns than in older children or adults?
A.Eosinophils
B.Lymphocytes
C.Monocytes
D.Neutrophils

D.Neurosyphilis

Neutrophils may appear in CSF from many causes,making it necessary to correlate results of chemicalassays with hematologic findings. Low glucose andhigh protein occur in both malignancy and bacterialmeningitis. Tumor markers and lactate may be helpful in distinguishing malignancy from bacterialmeningitis. In neurosyphilis, there is usually anabsolute lymphocytosis, increased total protein and IgG index.

16.Neutrophilic pleocytosis is usually associated with all of the following except:
A.Cerebral infarction
B.Malignancy
C.Myelography
D.Neurosyphilis

C Although the blood-brain barrier excludes most plasma proteins, abnormal serum proteins can cause parallel CSF electrophoretic patterns. Therefore, an abnormal CSF pattern indicates CNS disease only if not duplicated by the serum pattern. Normal CSF total protein in newborns may be up to two times higher than adult levels. Antibodies to T. pallidum remain in CSF after treatment, but non-treponemal antibodies disappear. While the FTA-ABS test for specific antibodies is more sensitive, the VDRL test is often performed concurrently. A positive result for both tests is diagnostic of active tertiary syphilis.

17.Which statement about CSF protein is true?
A. An abnormal serum protein electrophoretic pattern does not affect the CSF pattern
B. The upper reference limit for CSF total protein in newborns is one-half adult levels
C.CSF IgG is increased in panencephalitis, malignancy, and neurosyphilis
D. Antibodies to Treponema pallidum disappear after successful antibiotic therapy

D A culture should be performed on the sediment of the third aliquot of the CSF after it is centrifuged. Blood and chocolate agar and anaerobic broth should always be used, and, if sterile, held a minimum of 3 days. Blood cultures should be done since septicemia occurs in about one-half of bacterial meningitis cases. A Gram stain is always performed using sediment of the CSF because it is positive in more than 70% of acute bacterial meningitis cases. India ink, acid-fast, and wet preparations may be ordered if an absolute monocytosis is present.

Which of the following statements regarding routine microbiological examination of CSF is true?
A.A Gram stain is performed on the CSF prior to concentration
B .The Gram stain is positive in fewer than 40% of cases of acute bacterial meningitis
C. India ink and acid fast stains are indicated if neutrophilic pleocytosis is present
D. All CSF specimens should be cultured using sheep blood agar, chocolate agar, and supplemented broth

B Group B Streptococcus and E. coli are the two most common isolates in neonates. Haemophilus influenzae, S. pneumoniae, and N. meningitidis are the most common isolates in children. S. pneumoniae is the most frequent isolate in the elderly.

Which organism is the most frequent cause of bacterial meningitis in neonates?
A.Neisseria meningitidis
B.Group B Streptococcus
C.Streptococcus pneumoniae
D.Klebsiella pneumoniae

C In cases of trauma, it may be necessary to differentiate rhinorrhea from CSF leakage, and this can be done by immunofixation electrophoresis to identify tau protein found in CSF but not serum. Tau protein is an enzymatically modified form of transferrin that migrates in the slow beta zone just behind unmodified transferrin. Transthyretin or prealbumin is present in far greater concentration in CSF than blood but may not be seen if CSF is diluted with nasal fluid. Myelin basic protein is a component of nerve sheaths and is present in CSF in about 60%of persons with MS. It is also found in persons with other demyelinating diseases, SLE, stroke and brain injury. C-reactive protein is elevated in the CSF of approximately two-thirds of persons with bacterial meningitis.

Following a head injury, which protein will identify the presence of CSF leakage through the nose?
A. Transthyretin
B. Myelin basic protein
C. Tau protein
D.C-reactive protein

B The serous fluids include pleural, pericardial, and peritoneal fluid. They form from ultrafiltration of plasma through serous membranes. These are lined with specialized epithelium called mesothelium. They comprise about 5% of the cells in serous fluid and may be difficult to differentiate from malignant cells. Pleural fluid volume is normally less than 10 mL. The volume of pericardial fluid is normally 10-50 mL and peritoneal fluid 30-50 mL. X-rays can detect an increase in serous fluids of 300 mL or more. Normal serous fluids are clear and range in color from straw to light yellow.

Which of the following statements regarding serous fluids is true?
A. The normal volume of pleural fluid is 30-50 mL
B. Mesothelial cells, PMNs, lymphocytes, and macrophages may be present in normal fluids
C.X-ray can detect a 10% increase in the volume of a serous fluid
D.Normal serous fluids are colorless

C Effusions are classified as either transudates, exudates, or chylous. Transudates result from abnormal hemodynamics (e.g., congestive heart failure, liver disease), and exudates and chylous fluids from local disease. A pleural fluid that is purulent is called an empyemic fluid. Such a fluid has a WBC count of 10,000/μL or greater.

22. The term effusion refers to:
    A.A chest fluid that is purulent
    B.A serous fluid that is chylous
    C. An increased volume of serous fluid
    D. An inflammatory process affecting the appearance of a serous fluid

C Transudative fluids are distinguished from exudative fluids by the physical appearance, cellularity, SG, total protein, LD, cholesterol, and bilirubin. Exudative fluids have a fluid:serum LD ratio greater than 0.6 caused by release of the enzyme from inflammatory or malignant cells. Exudative fluids have a total protein greater than3.0 g/dL, SG greater than 1.015, fluid:serum total protein ratio greater than 0.6, cholesterol greater than60 mg/dL (fluid:serum ratio > 0.3) and fluid:serum bilirubin ratio greater than 0.6. Exudates are caused by infection, infarction, malignancy, rheumatoid diseases, and trauma.

Which of the following laboratory results is characteristic of a transudative fluid?
A.SG = 1.018
B.Total protein = 3.2 g/dL
C.LD fluid/serum ratio = 0.25
D.Total protein fluid/serum ratio = 0.65

C Xanthochromia indicates either an exudative processor prior traumatic tap. Hemorrhagic pleural fluids usually have RBC counts greater than 100,000/μL and are usually caused by lung neoplasms. Clearing of fluid or diminished RBC counts in successive tubes favors a diagnosis of a traumatic tap. A clot may for min a hemorrhagic fluid or following a traumatic tap. However, a transudative fluid will not clot.

24.Which observation is least useful in distinguishing a hemorrhagic serous fluid from a traumatic tap?
A.Clearing of fluid as it is aspirated
B.Presence of xanthochromia
C.The formation of a clot
D.Diminished RBC count in successive aliquots

A Normal fluids have a WBC count less than 1,000/μL,but counts between 1,000 and 2,500/μL may be seen in both exudates or transudates. All WBC types are present, but no type should account for more than50% of the leukocyte count. An RBC count below10,000/μL is usually caused by a traumatic tap. A fluid hematocrit similar to blood is caused by a hemothorax. Pleural fluids containing > 100,000/μLRBCs are associated most often with malignancies, but are also seen in trauma and pulmonary infarction.

25.Which of the following laboratory results on a serous fluid is most likely to be caused by atraumatic tap?
A. An RBC count of 8,000/μL
B.A WBC count of 6,000/μL
C.A hematocrit of 35%
D.A neutrophil count of 55%

B Transudative fluids are caused by circulatory problems, usually decreased oncotic pressure or increased hydrostatic pressure. In contrast, exudative effusions are caused by inflammatory processes and cellular infiltration as seen in malignancy. In addition to a RBC count > 100,000/μL, malignancies often involve the lung, colon, breast, or pancreas and often produce carcinoembryonic antigen.

26.Which of the following conditions is commonly associated with an exudative effusion?
A.Congestive heart failure
B.Malignancy
C.Nephrotic syndrome
D.Cirrhosis

D Malignancy, pulmonary infarction, SLE, and RA are characterized by inflammation with increases in protein, WBCs, and LD. Exudates can also be caused by tuberculosis, pancreatitis, and lymphoma. Lymphatic obstruction is often associated with lymphoma and other malignancies that block the flow of lymph into the azygous vein. This causes a chylous effusion. Chylous effusions are also caused by traumatic injury to the thoracic duct. Necrosis causes a pseudochylous effusion. This resembles a chylous effusion in appearance but has a foul odor. Chylous fluids contain chylomicrons, stain positive for fat globules, show lymphocytosis, and have a triglyceride concentration over twofold higher than plasma (or > 110 mg/dL). Pseudochylous effusions are characterized by mixed cellularity and elevated cholesterol.

27.Which of the following conditions is associated with a chylous effusion?
A.Necrosis
B.Pulmonary infarction or infection
C.Systemic lupus erythematosus or rheumatoid arthritis
D.Lymphatic obstruction

C Normal pleural fluid has the same glucose concentration as plasma. Hyperglycemia is the only condition that is associated with a high pleural fluid glucose. Low glucose levels (<60 mg/dL) may be seen in infection, malignancy, and rheumatic diseases. However, glucose levels are lowest (often below 30 mg/dL) and are a constant finding when rheumatoid disease affects the lungs. Pancreatitis causes an exudative peritoneal and pleural effusion with an elevated peritoneal fluid amylase (without a low glucose).

28.Which of the following conditions is most often associated with a pleural fluid glucose below 30 mg/dL?
A.Diabetes mellitus
B.Pancreatitis
C.RA
D.Bacterial pneumonia

D The pH of pleural fluid is approximately 7.64, and values below 7.30 are usually associated with a poorer prognosis and usually require drainage. Esophageal rupture produces the lowest pH with values in the range of 6.0-6.3. In addition, pleural fluid pH is low in rheumatoid disease involving the lungs and pleura, some malignancies, and SLE. Low pH and glucose in pleural fluid are seen in lung abscess and exudative bacterial pneumonia (called parapneumonic effusion). Pneumothorax results from air entering the pleural space and does not produce a low pH.

29.In which condition is the pleural fluid pH likely to be above 7.3?A.Bacterial pneumonia with parapneumonic exudate
B.Rheumatoid pleuritis
C.Esophageal rupture
D.Pneumothorax

D Synovial fluid has approximately the same SG and glucose as plasma and the serous fluids but is far more viscous due to a high content of mucoprotein (hyaluronate) secreted by the synovium. Viscosity is estimated by pulling the fluid from the tip of a syringe or pipet. Normal fluid gives a string longer than 4 cm. Low viscosity indicates inflammation. The total protein of synovial fluid is usually lower than serous fluids, the upper reference limit being 2.0 g/dL.

31.Which of the following characteristics is higher for synovial fluid than for the serous fluids?
A.SG
B. Glucose
C. Total protein
D. Viscosity

A Septic arthritis

The WBC count is elevated in all types of arthritis, but is greatest (50,000-100,000/μL) in septic arthritis. Neutrophils comprise less than 25% of WBCs in normal and non-inflammatory arthritis, but are above50% in inflammatory and septic arthritis. Fluids are diluted in saline because acetic acid causes a mucin clot to form. WBC counts should be performed within1 hour of collection because the WBC count will diminish over time.

32.In which type of arthritis is the synovial WBC count likely to be greater than 50,000/μL?
A. Septic arthritis
B. Osteoarthritis
C.RA
D. Hemorrhagic arthritis

B Ragocytes are PMNs containing dark granules composed of immunoglobulins, but they may be seen in gout and septic arthritis as well as RA. LE cells may be seen in fluid from patients with SLE. Reiter's cells, macrophages with ingested globular inclusions, are seen in Reiter's syndrome and other inflammatory diseases.

33.What type of cell is a "ragocyte"?
A. Cartilage cell seen in inflammatory arthritis
B.A PMN with inclusions formed by immune complexes
C.A plasma cell seen in RA
D. A macrophage containing large inclusions

A Although all of the crystals mentioned can cause crystal-induced arthritis, uric acid and sodium urate crystals cause gout and are seen in about 90% of gout patients.

34.Which of the following crystals is the cause of gout?
A.Uric acid or monosodium urate
B.Calcium pyrophosphate or apatite
C.Calcium oxalate
D.Cholesterol

B Calcium pyrophosphate crystals occur as needles or small rhombic plates and can be confused with uric acid. They rotate plane polarized light but not as strongly as uric acid. Synovial fluid should never be collected in tubes containing powdered ethylenediaminetetraacetic acid (EDTA) because it may form crystals that can be mistaken for in vivo crystals. The recommended anticoagulant is sodium heparin, although liquid EDTA may be used.

35.Which crystal causes "pseudogout"?
A.Oxalic acid
B.Calcium pyrophosphate
C.Calcium oxalate
D.Cholesterol

C Polarized microscopy with a red compensating filter differentiates uric acid and pseudogout crystals. When the long axis of uric acid needles is parallel to the slow vibrating light, the crystals appear yellow. When the long axis is perpendicular to the slow vibrating light, the crystals appear blue. Calcium pyrophosphate gives the reverse effect.

36. A synovial fluid sample is examined using a polarizing microscope with a red compensating filter. Crystals are seen that are yellow when the long axis of the crystal is parallel to the slow vibrating light. When the long axis of the crystal is perpendicular to the slow vibrating light, the crystals appear blue. What type of crystal is present?
    A.Calcium oxalate
    B.Calcium pyrophosphate
    C.Uric acid
    D.Cholesterol

C Synovial fluid glucose is normally less than 10 mg/dL below the serum glucose, and should be collected after an 8-hour fast to ensure that the fluid and plasma are equilibrated. In septic arthritis, the glucose level is often more than 40 mg/dL below the serum level and about 25-40 mg/dL lower in inflammatory arthritis, which includes gout. Osteoarthritis and hemorrhagic arthritis are not usually associated with low joint fluid glucose.

37.In which condition is the synovial fluid glucose most likely to be within normal limits?
A.Septic arthritis
B.Inflammatory arthritis
C.Hemorrhagic arthritis
D.Gout

A Rheumatoid factor can be present in both serum and synovial fluids from patients with RA, SLE, and other inflammatory diseases. Rheumatoid factor is present in synovial fluid of approximately 60% of patients with RA. Normally, IgG in synovial fluid is about 10% of the serum IgG level. CH50levels in serum and synovium are more differential. Both are increased in Reiter's syndrome but are often low in SLE; synovial CH50is decreased and serum CH50isnormal (or increased) in RA.

38.Which statement about synovial fluid in RA is true?A.Synovial/serum IgG is usually 1:2 or higher
B.Total hemolytic complement is elevated
C.Ninety percent of RA cases test positive for rheumatoid factor in synovial fluid
D.Demonstration of rheumatoid factor in joint fluid is diagnostic for RA

B Synovial fluid is normally sterile, and all of the organisms listed may cause septic arthritis. N. gonorrhoeaeis responsible for about 75% of septic arthritis cases occurring in young and middle-aged adults. Staphylococcus spp. is responsible for the majority of cases involving the elderly, and is the most frequently found isolate from infected joint replacements. Haemophilus spp., Staphylococcus spp.,and Streptococcus spp. are the most common causes of arthritis in young children.

39.Which of the following organisms accounts for the majority of septic arthritis cases in young andmiddle-age adults?
A.H. influenzae
B.Neisseria gonorrhoeae
C.Staphylococcus aureus
D.Borrelia burgdorferi

A Amniotic fluid bilirubin reflects the extent of fetal RBC destruction in cases of hemolytic disease of the newborn (HDN). It is measured by scanning the fluid from 350 to 600 nm, then drawing a baseline using the points at 365 nm and 550 nm. The delta absorbance (ΔA) of hemoglobin at 410 nm and bilirubin at 450 nm are determined by subtracting the absorbance of the baseline from the respective peaks. Samples that are not grossly hemolyzed can be corrected for oxyhemoglobin by subtracting 5% of the ΔA at 410 nm from the ΔA at 450 nm. When hemolysis is severe or meconium is present, the bilirubin must be extracted in chloroform before measuring absorbance. Bilirubin normally decreases with increasing gestational age because fetal urine contributes more to amniotic fluid volume as the fetus matures. The bilirubin concentration must be correlated with gestational age in order to correctly evaluate the severity of HDN.

Which of the following statements about amniotic fluid bilirubin measured by scanning spectrophotometry is true?
A. The 410-nm peak is due to hemoglobin and the 450-nm peak is due to bilirubin
B. Baseline correction is not required if a scanning spectrophotometer is used
C. Chloroform extraction is necessary only when meconium is present
D.In normal amniotic fluid, bilirubin increases with gestational age

C Amniotic fluid bilirubin is the best index of the severity of HDN and is measured by scanning or diode array spectrophotometry across the 550-365 nm range. When hemoglobin produces a positive slope at 410 nm, the bilirubin should be extracted with chloroform prior to scanning. Extraction methods give the best correlation with RBC destruction.

Which test best correlates with the severity of HDN?
A. Rh antibody titer of the mother
B. Lecithin/sphingomyelin (L/S) ratio
C. Amniotic fluid bilirubin
D. Urinary estradiol

B Respiratory distress syndrome develops when surfactants are insufficient to prevent collapse of the infant's alveoli during expiration. Tests measuring pulmonary phospholipid surfactants are the most specific and sensitive indicators of respiratory distress syndrome. An L/S ratio greater than 2:1 (in some laboratories 2.5:1) is the most widely accepted measure of fetal lung maturity. Most of the surfactants in the amniotic fluid are present in the form of lamellar bodies. These can be counted using an electronic cell counter at the settings for enumerating platelets.

3.Which is the reference method for determining fetal lung maturity?A.Human placental lactogen
B.L/S ratio
C.Amniotic fluid bilirubin
D.Urinary estriol

A Pulmonary surfactants are mainly disaturated lecithins produced by type II granular pneumocytes. The L/S ratio increases toward the end of the third trimester due to increased production of lecithin. The concentration of sphingomyelin remains constant throughout gestation and serves as an internal reference. Meconium contains less lecithin than amniotic fluid and will usually decrease the L/S ratio; however, meconium produces a spot that can be misinterpreted as lecithin, leading to a falsely increased L/S ratio. Sufficient PG to produce a spot is seen only when the L/S ratio is 2:1 or higher. PG is not present in either blood or meconium and, therefore, its presence indicates fetal lung maturity. In diabetes, the fetal lungs may mature more slowly than normal, and infants may develop RDS when the L/S ratio is 2:1 or slightly higher. For this reason, an L/S of 3:1 more closely correlates with fetal lung maturity wh

Which of the following statements regarding the L/S ratio is true?
A.A ratio of 2:1 or greater usually indicates adequate pulmonary surfactant to prevent respiratory distress syndrome (RDS)
B.A ratio of 1.5:1 indicates fetal lung maturity in pregnancies associated with diabetes mellitus
C. Sphingomyelin levels increase during the third trimester, causing the L/S ratio to fall slightly during the last 2 weeks of gestation
D.A phosphatidylglycerol (PG) spot indicates the presence of meconium in the amniotic fluid

C Pulmonary surfactants are largely present in the form of lamellar bodies and can be lost by centrifuging the amniotic fluid at high g force. Centrifuge speed should be the minimum required to spin down cells(450 g for 10 minutes at 4°C). Samples that cannot be measured immediately should be refrigerated or frozen. Samples are stable for up to 3 days at 2°C-8°C and for months when frozen at -20°C or lower. Meconium and blood may also introduce errors when measuring the L/S ratio. Blood has an L/S ratio of approximately 2:1 and will falsely raise the L/S ratio when fetal lungs are immature and depress the L/S ratio when fetal lungs are mature.

Which of the following conditions is most likely to cause a falsely low L/S ratio?
A.The presence of PG in amniotic fluid
B.Freezing the specimen for one month at -20°C
C.Centrifugation at 1,000 × gfor 10 minutes
D.Maternal diabetes mellitus

B In normal pregnancy, hCG levels rise exponentially following implantation and peak at weeks 9-12,reaching in excess of 100,000 mIU/mL. Levels fall after the first trimester to about 20,000 mIU/mL and then remain at about that level through term. The hCG doubling time averages 2.2 days. In ectopic pregnancy, the expected increase between consecutive days is below normal. Hydatiform moles are associated with greatly elevated levels of hCG. Serum hCG can take up to 4 weeks to return to nonpregnant (<25 mIU/mL) or baseline (<5 mIU/mL)levels following delivery, stillbirth, or abortion.

Which of the following statements accurately describes hCG levels in pregnancy?
A. Levels of hCG rise throughout pregnancy
B. In ectopic pregnancy, serum hCG doubling time is below expected levels
C. Molar pregnancies are associated with lower levels than expected for the time of gestation
D. hCG returns to nonpregnant levels within 2 days following delivery, stillbirth, or abortion

C The α subunit of hCG is very similar to the α subunit of TSH and FSH and identical to LH. Although the β subunits of hCG and LH are very similar, antibodie scan be made to the β subunit of hCG that do not cross-react with LH or other pituitary hormones. Most enzyme immunoassay (EIA) methods utilize two monoclonal antibodies against different sites of the hCG molecule. One antibody is specific for the carboxyterminal end of the β chain, and the other reacts with the α chain, resulting in a positive test only when intact hCG is present. Because monoclonal antibodies arederived from mouse hybridomas, rare false positives may occur in patients who have antimouse Ig antibodies. Although the test can detect lower levels of hCG, 25 mIU/mL is the positive cutoff point for pregnancy. Serum is preferred over urine because serum levels are more consistently above the cut off point than random urine in very early pregnancy.

Which of the following statements regarding pregnancy testing is true?
A.βSubunits of human chorionic gonadotropin(hCG), thyroid-stimulating hormone (TSH),and follicle-stimulating hormone (FSH) are very similar
B. Antibodies against the βsubunit of hCG cross-react with luteinizing hormone (LH)
C.A false-positive result may occur in patients with heterophile antibodies
D.Serum should not be used for pregnancy tests because proteins interfere

C Assays of intact hCG are double antibody sandwich immunoassays. One antibody reacts with the α subunit and the other with the β subunit. In assays where both antibodies are added together, a process called the "hook effect" is known to occur. In extreme antigen excess, the hCG saturates both antibodies, preventing sandwich formation. This results in a falsely low measurement of hCG.

SITUATION:A pregnant female was seen by her physician who suspected a molar pregnancy. An hCG test was ordered and found to be low. The sample was diluted 10-fold and the assay was repeated. The result was found to be grossly elevated. What best explains this situation?
A.The wrong specimen was diluted
B.A pipeting error was made in the first analysis
C.Antigen excess caused a falsely low result in the undiluted sample
D.An inhibitor of the antigen-antibody reaction was present in the sample

B Down syndrome can result from a 14-21 translocationor isochromosome formation, but most cases arise from nondisjunction of chromosome 21 during meiosis. A quad marker screen consisting of maternal serum AFP, hCG, dimeric inhibin A, and unconjugated estriol is used to screen for Down syndrome during the second trimester. If the test is positive, amniocentesis is performed, and 21 trisomy is investigated by chromosome karyotyping or FISH.

Most cases of Down syndrome are the result of:
A.Nondisjunction of an E chromosome (E trisomy)
B.Nondisjunction of chromosome 21 (G trisomy)
C.A 14-21 chromosome translocation
D.Deletion of the long arm of chromosome 21

A Estriol is produced by the placenta as well as the fetal and maternal adrenal glands and liver. Free estriol produced by the placenta is rapidly conjugated by the maternal liver. Maternal serum unconjugated(free) estriol is almost all derived from the fetus and is a direct reflection of current fetal placental function. Serum unconjugated estriol (uE3) measured during the second trimester is used along with serum AFP,hCG, and dimeric inhibin A as part of the quad marker screening test for Down syndrome. AFP anduE3are decreased by approximately 25%, inhibin A is increased by a factor of approximately 1.8, and hCG is increased by a factor of approximately 2.5 in Down syndrome pregnancies. When all four assays are combined with adjustments for maternal age, gestational age, race, maternal weight, and diabetes, the detection rate is approximately 70-80% and the false-positive rate 7%.

Which assay result is often approximately 25%below the expected level in pregnancies associated with Down syndrome?
A.Serum unconjugated estriol
B.L/S ratio
C.Amniotic fluid bilirubin
D.Urinary chorionic gonadotropin

C Spermatozoa have a well-defined headpiece consisting of the acrosome and nucleus. The acrosome comprises the anterior portion of the head, and contains nutrients and enzymes needed for penetration of the ovum. A thin filament, the neckpiece, connects the head and tail. The tail is divided into the midpiece, principal piece(mainpiece), and endpiece. The midpiece is the thick anterior end of approximately 5 μ containing a 9 + 2longitudinal arrangement of microtubules (two central microtubules surrounded by nine doublets so that across section appears like a pinwheel). This is called the axoneme and is surrounded by nine radial fibers. The longest portion of the tail (40-45 μ) is the principal piece. It is thinner than the midpiece and lacks the outer radial fibers. The distal portion, called the endpiece, is approximately 5 μ. It contains the axoneme but is unsheathed.

What is the term for sperm when the anterior portion of the headpiece is smaller than normal?
A.Azoospermia
B.Microcephaly
C.Acrosomal deficiency
D.Necrozoospermia

C Varicocele is the hardening of veins that drain the testes. This causes blood from the adrenal vein to flow into the spermatic vein. Adrenal corticosteroids retard the development of spermatozoa. Mumps,Klinefelter's syndrome, and malignancy cause testicular failure which accounts for about 10% of infertility cases in men.

What is the most common cause of male infertility?A.Mumps
B.Klinefelter's syndrome
C.Varicocele
D.Malignancy

A the reference range for spermatozoa is 15-150 ×106/mL. Concentrations below 15 × 106/mL are considered abnormal. The sperm concentration is multiplied by the seminal fluid volume to determine the sperm count. The lower limit of normal for the sperm count is 40 × 106per ejaculate. This often results from obstruction of the ejaculatory duct or testicular failure.

Which of the following values is the lower limit of normal for sperm concentration?
A.15 million per mL
B.40 million per mL
C.60 million per mL
D.100 million per mL

A Acrosomal deficiency, nuclear abnormalities, and lengthened neckpiece are the most common morphological abnormalities of spermatozoa. Tapering of the head is a nuclear abnormality. Sperm morphology should be evaluated by classifying 200mature sperm in duplicate by strict criteria. There are several strict criteria in use. The normal sperm head is approximately 4.0-5.0 μm in length, 2.5-3.5 μm in width, has a L:W ratio of 1.3-1.8, and an acrosomal area of 40%-70%. Using strict criteria, there is a high likelihood of infertility when the number of normal forms is below 4%.

Which morphological abnormality of sperm is most often associated with varicocele?
A.Tapering of the head

B.Cytoplasmic droplet below the neckpiece
C.Lengthened neckpiece
D.Acrosomal deficiency

A Eosin Y is excluded by living sperm and is used to determine the percentage of living cells. Papanicolaou, Giemsa's, and hematoxylin stains are used to evaluate sperm morphology. The viability test should be performed whenever the results of the motility test are subnormal.

Which of the following stains is used to determine sperm viability?A.Eosin Y
B.Hematoxylin
C.Papanicolaou
D.Methylene blue

A The normal volume of seminal fluid is 1.5-5.0 mL. A lower volume than 1.5 mL causes a low sperm count (sperm/mL × volume) and can be caused by absence of the seminal vesicles or prostate, ductal obstruction, or retrograde ejaculation of seminal fluid into the urinary bladder. The seminal fluid should coagulate within 5 minutes after ejaculation owing to secretions of the seminal vesicles. Proteases such as PSA hydrolyze semenogelin and fibronectin,causing liquefaction to occur within 1 hour at room temperature. The seminal fluid pH should be between 7.2 and 8.0. Motility is evaluated by grading the movement of 2 replicates of 200 sperm in 5 high-power fields. It is normal when ≥ 32% show progressive movement or when ≥ 40% show progressive and nonprogressive movement.

Which of the following semen analysis results is abnormal?
A.Volume 1.0 mL
B. Liquefaction 40 minutes at room temperature
C.pH 7.6
D.Motility 50% progressive movement

B A seminal fluid sample should not be collected following coitus. The patient should abstain from ejaculation for at least 2 days but no more than 7 days prior to submitting the sample. A condom should not be used because it may contain spermicides. The sample should be collected at the testing site in a sterile jar with a wide opening, and stored at room temperature. The specimen should be analyzed as soon as possible. The time between collection and delivery to the lab must be documented. Motility should be determined as soon as the fluid has liquefied (maximum storage time is 1 hour). Anticoagulants are not used; if the sample fails to liquefy, it can be treated with chymotrypsin before analysis.

Which of the following sample collection and processing conditions will lead to inaccurate seminal fluid analysis results?
A.Sample stored at room temperature for 1 hour before testing
B.Sample collected following coitus
C.Sample collected without an anticoagulant
D.Sample collected without use of a condom

A When evaluating sperm morphology, the number of immature spermatozoa and white blood cells (round cells) should also be determined. The number of each is counted along with 200 mature sperm, then divided by 2 to determine their percentage. This is multiplied by the sperm concentration to give the absolute count per mL. An increased number of WBCs is an indicator of infection and is usually associated with prostatitis. Round cells are also estimated by noting their number per high-powerfield. Each round cell per field counted with the 40× objective corresponds to one million per mL. The upper limit of normal for WBCs is 1 × 106/mL, and for immature sperm 5 × 106/mL.

When performing a seminal fluid analysis, what is the upper limit of normal for WBCs?
A.1 × 106/mL
B.5 × 106/mL
C.10 × 106/mL
D.20 × 106/mL

C Fructose is the primary nutrient in the seminal fluid and is needed for motility. It is supplied by the seminal vesicles, and is low when the vas deferens or seminal vesicles are absent. The lower limit of normal is 150 mg/dL or13 μmol per ejaculate.

Which carbohydrate measurement is clinically useful when performing a seminal fluid analysis?
A.Glucose
B.Galactose
C.Fructose
D.Maltose

B Peptic ulcer disease may be caused by either gastric or duodenal ulcers, which are associated with discomfort, hyperacidity, and bleeding. Hyperacidity is most often caused by H. pylori infection, which can cause both gastric and duodenal ulcers. In the absence of a positive test for H. pylori (e.g., endoscopic biopsy, breath test, ELISA, PCR) and no history of drug induced ulcers, Zollinger-Ellison syndrome (gastrinoma) should be suspected, and can usually be identified by a plasma gastrin assay. Cancer of the stomach is associated with increased gastric fluid volume but not hyperacidity. Pernicious anemia is associated with gastric hypoacidity, and not ulcers.

Which condition is most often associated with gastric ulcers?A. Cancer of the stomach
B.H. pylori infection
C.Zollinger-Ellison (Z-E) syndrome
D.Pernicious anemia

C Gastrin is produced by specialized epithelium of the stomach and stimulates secretion of HCl by parietal cells. Secretion is controlled by negative feedback causing levels to be high in conditions associated with a chlorhydria such as atrophic gastritis. Zollinger-Ellison syndrome results from a gastrin-secreting tumor, gastrinoma, usually originating in the pancreas. It is characterized by very high levels of plasma gastrin and excessive gastric acidity. In duodenal ulcers, increased gastric acidity occurs, but fasting plasma gastrin levels are normal. However, postprandial gastrin levels maybe elevated in these patients because they do not respond to the negative feedback signal caused by HCl release. In stomach cancer, gastric volume is increased but acidity is not, and plasma gastrin levels are variable.

In which condition is the highest level of serum gastrin usually seen?A.Atrophic gastritis
B.Pernicious anemia
C.Z-E syndrome
D.Cancer of the stomach

A Blood in feces is a very sensitive indicator of gastrointestinal bleeding, and is an excellent screening test to detect asymptomatic ulcers and malignancy of the gastrointestinal tract. However, the test is nonspecific and contamination with vaginal blood is a frequent source of error.

Which of the following is commonly associated with occult blood?A.Colon cancer
B.Atrophic gastritis
C.Pernicious anemia
D.Pancreatitis

A.Fluid to serum triglyceride ratio

A pleural fluid submitted to the laboratory is milky in appearance. Which test would be most useful in differentiating between a chylous and pseudochylous effusion?
A.Fluid to serum triglyceride ratio
B.Fluid WBC count
C.Fluid total protein
D.Fluid to serum LD ratio

D CSF glucose is approximately 60% of the plasma glucose, but may be somewhat lower in a diabetic person. The reference range is approximately 40-70 mg/dL. A CSF glucose level above 70 mg/dL is caused by a high plasma glucose that equilibrated with the CSF. Therefore,hyperglycorrhachia is caused by hyperglycemia.The WBC count in a child between 5-12 years is 0-10 × 106/L (0-10/μL). The normal RBC count and protein rule out subarachnoid hemorrhage and traumatic tap. Although aseptic meningitis cannot be ruled out conclusively, it is unlikely given a normal WBC count and IgG

A cerebrospinal fluid sample from an 8-year-oldchild with a fever of unknown origin was tested for glucose, total protein, lactate, and IgG index. The glucose was 180 mg/dL but all other results were within the reference range. The CSF WBC count was 9 × 106/L and the RBC count was 10 × 106/L. The differential showed 50% lymphocytes, 35% monocytes, 10% macrophages, 3% neutrophils, and 2% neuroectodermal cells. What is the most likely cause of these results?

A.Aseptic meningitis
B.Traumatic tap
C.Subarachnoid hemorrhage
D.Hyperglycemia

A Bloody, exudative fluids with a preponderance of a singular cell type are suggestive of malignancy. The cellularity in malignancy is variable but lymphocytosis occurs in about half of cases. Mesothelial cells normally comprise less than 10% of the cells in serous fluid. They may be resting cells, reactive, degenerated,or phagocytic in nonmalignant conditions. In inflammatory conditions, they are often increased and resemble macrophages. However, clusters or balls of such cells and paper-punch vacuoles throughout the cytoplasm and over the nucleus are characteristics of malignant mesothelial cells. Such cells secrete hyaluronic acid, making the fluid highly viscous. The gross appearance of this fluid suggests malignancy.The description of these cells points to mesothelioma, and this specimen should be referred for cytological examination in order to confirm the diagnosis.

A WBC count and differential performed on ascites fluid gave a WBC count of 20,000μL with90% macrophages. The gross appearance of the fluid was described by the technologist as "thick and bloody." It was noted on the report that several clusters of these cells were observed and that the majority of the cells contained many vacuoles resembling paper-punch holes. What do the observations above suggest?
A.Malignant mesothelial cells were counted as macrophages
B.Adenocarcinoma from a metastatic site
C.Lymphoma infiltrating the peritoneal cavity
D.Nodular sclerosing type Hodgkin's disease

A hCG may be produced in men by tumors of trophoblastic origin, such as teratoma and seminoma, and is an important marker for nontrophoblastic tumors, as well.

A quantitative serum hCG is ordered on a male patient. The technologist should:
A.Perform the test and report the result
B.Request that the order be cancelled
C.Perform the test and report the result if negative
D.Perform the test and report the result only ifgreater than 25 IU/L

C CSF samples will not clot as a result of a subarachnoid hemorrhage. While the sample is still suitable for microbiological analysis, it will not give reliable cell counts or biochemistry results owing to extensive contamination with peripheral blood.

A CSF sample submitted for cell counts has a visible clot. What is the best course of action?
A.Count RBCs and WBCs manually after diluting the fluid with normal saline
B.Tease the cells out of the clot before counting,then dilute with WBC counting fluid
C.Request a new sample
D.Perform a WBC count without correction

A Cellular distortion caused by centrifugation is a common problem, and can be reduced by adding22% bovine albumin or 10% dextran to the cytospin cup along with the sample. CSF does not clot because it contains no fibrinogen, and the sample can be collected and counted without anticoagulant.

A CSF CytoPrep smear shows many smudge cells and macrophages with torn cell membranes. What most likely caused this problem?A.Failure to add albumin to the cytospin cup
B.Failure to collect the CSF in EDTA
C.Centrifuge speed too low
D.Improper alignment