body fluids exam 4

What are the 3 "phases" of a total lab QA program?

Preanalytical, analytical, & postanalytical phases

What would be a cause to reject a sample?

No label, no requisition, leaking container, or QNS

Documentation of personnel education and training falls into which phase?

Analytical

What is the minimum number of controls that should be used for any test in the lab?

2

Other than deionized water, what other solutions can be used to calibrate a refractometer?

9% sucrose or 5% saline

How often should centrifuges be calibrated?

Every 3 months

How frequently should the temperature of refrigerators be recorded?

Daily

What term describes the ability to reproduce a test result?

Precision

What term is used when both accuracy and precision are maintained?

Reliability

What term is used to describe a gradual upward movement of values away from the mean?

Trend

What term is used to describe an abrupt movement of values either above or below the mean, 6 consecutive times?

Shift

How often may a random error occur?

1 in 20 analyses

What is a cause of a trend?

Deteriorating reagent & deteriorating instrument component

What is proficiency testing?

External QC samples are received from an outside agency; results are compared to other participants

What is the biggest source of error in the postanalytical phase?

Clerical mistakes

According to CLIA, what are the 4 basic levels of lab testing?

Waived, provider-performed microscopy, moderate complexity, & high complexity

What urine tests are considered "waived" according to CLIA?

Dipstick/tablet tests & pregnancy tests

In which CLIA testing category do urine microscopics fall?

Provider-performed microscopy

Which urine tests are considered high complexity?

None

What term is used to describe an unanticipated tragedy or death not related to a patient's reason for admission to the hospital?

Sentinel event

What term describes the combined process of reducing both test time and test errors?

Lean six sigma

What is the biggest variable among lab scientists when it comes to manual dipstick testing?

Color discrimination

What is the basic principle of operation of most dipstick readers?

Reflectance photometry

What is meant by bi-directional interface?

Lab computer & testing instruments talk to each other

What are the functions of amniotic fluid?

Cushions fetus, allows for movement and growth, maintain even temp, & biochemical hemostasis

What is a trans-abdominal needle aspiration with ultrasound called?

Amniocentesis

When can an amniocentesis be performed safely?

14 weeks gestation

Ideally, why should the first 2-3 mL of amniotic fluid that is drawn off be discarded?

May contain mom's blood which could interfere in some tests

What are the risks of amniocentesis?

Trauma to fetus, cord or placenta which can lead to hemorrhage, infection, pre-mature labor, or miscarriage

What is the color and clarity of normal amniotic fluid?

Colorless to pale yellow & clear

What could be the cause of dark red-brown amniotic fluid?

Fetal death

An intense yellow color to amniotic fluid is suspicious for the presence of what substance?

Bilirubin

What 2 possible situations could contribute to a bloody amniotic fluid?

Traumatic tap or fetal hemorrhage

A green amniotic fluid is suspicious for the presence of what substance?

Meconium

What test/procedure can help differentiate maternal red cells from fetal cells?

Kleihauer-Betke stain

A possible bladder puncture (urine) can be differentiated from amniotic fluid by performing what tests?

Creatinine, urea, protein, & fern test

What are expected results for creatinine and urea on urine compared to the same tests on amniotic fluid?

Urine: both higher; AF: both low

What are expected results for a fern test on urine compared to amniotic fluid?

Urine: neg; AF: pos

At what stage in a pregnancy should testing be done for neural tube defects?

16-18 weeks

At what stage in a pregnancy should testing be done for chromosome abnormalities?

16-18 weeks

At what stage in a pregnancy should testing be done for hemolytic disease of the newborn?

20-28 weeks

At what stage in a pregnancy should testing be done for fetal lung maturity?

34-42 weeks

At what stage in a pregnancy should testing be done for Chorioamnionitis (infection)?

34-42 weeks

What is the most common genetic cause of mental retardation?

Down's (trisomy 21)

What chromosome carries the gene for cystic fibrosis?

Chromosome 7

What is the leading cause of death in patients with cystic fibrosis?

Pneumonia

What is the genetic defect associated with Klinefelter's?

1 (or more) extra X chromosomes in a male; XXY or XXXY

Neural tube defects is linked to a dietary deficiency of what substance?

Folic acid

What substance is present in mom's serum (and amniotic fluid) when the fetus is affected by a neural tube defect?

Alpha fetoprotein

What regulated program has helped reduce the incidence of neural tube defects in the U.S.?

Folate fortification

What is erythroblastosis fetalis?

Hemolytic disease of the newborn

Why is the first blood type incompatible pregnancy typically NOT affected by hemolytic disease of the newborn?

Mom has made IgM antibodies which do not cross the placenta

What class of antibodies is capable of crossing the placenta?

IgG

Where does bilirubin come from?

Lysis of RBCs

What lab test is done to measure the level of bilirubin in amniotic fluid?

OD450

What is kernicterus?

Presence of bilirubin in brain tissue

What type of graph is used to determine the severity of anemia of the baby in utero?

Liley graph

How will exposure to room light affect a bilirubin result?

Falsely decrease

What is the leading cause of death of premature babies?

Respiratory distress syndrome

What is respiratory distress syndrome due to?

Deficiency in lung surfactants

What is a mixture of lipids, proteins, and carbs that maintain alveolar size/stability?

Surfactant

What 3 surfactants can be measured to assess fetal lung maturity?

Lecithin, sphingomyelin, phosphatidlyglycerol (PG)

What is the most commonly performed lab test done to assess fetal lung maturity?

PG

What is the sample requirement for a fetal fibronectin?

Cervical swab

What lab test is a negative predictor of delivery?

Fetal fibronectin (fern test also used)

What lab test is the best (and quickest) for detecting chorioamnionitis?

Gram stain

What are 2 conditions that could cause fresh blood in a stool sample?

Colon cancer & hemorrhoids

Other than blood, what could cause a stool sample to be red?

Beets or dyes

What is the appearance of a stool sample on a patient with bleeding stomach ulcers?

Dark & tarry

What is the appearance of a stool sample on a patient with a bile duct obstruction?

Gray or putty colored

What test can be performed on a newborn's stool to differentiate between baby blood and mommy blood?

APT test

The absence of urobilin and urobilinogen in feces suggests what clinical condition?

Bile duct obstruction

What term is used when fat is present in stool?

Steatorrhea

What is the appearance of a stool sample on a patient with steatorrhea?

Greasy, foamy, frothy

How many neutrophils can be seen per high power field in a normal stool sample?

Up to 3

What is the significance of 10 segs/hpf in a stool?

May indicate infection with a pathogen

What is the significance of 0 segs/hpf plus diarrhea?

May indicate a bacterial toxin

With what conditions are undigested muscle (meat) fibers in a stool sample consistent?

Pancreatic diseases, bile obstructions, & cystic fibrosis

What stains can be used to visualize fat droplets in stool?

Sudan & oil red O

What disease is the occult blood designed to screen for?

Colo-rectal cancer

What reagent (in the occult blood test pad) combines with hemoglobin and H2O2 to produce a blue color?

Guiac

What substances or situations can cause a false positive occult blood test?

Ingesting red meat or iron supplements, bleeding gums, some vegetables, & upper GI bleed (ulcer)

What could cause a false negative occult blood test?

Ascorbic acid or vitamin C

What disease is linked to gastrin-secreting tumors?

Zollinger-Ellison

What is anacidity?

Inability to make adequate HCl in the stomach

What disease is linked to anacidity and B12 deficiency?

Pernicious anemia

What stomach/pancreatic hormone stimulates the production of HCl?

Gastrin

In addition to fertility studies, why might a semen analysis be performed?

Evaluate a post-vasectomy & forensic purposes

When evaluating a semen sample for sperm morphology, how many sperm must be examined?

200

What microscopic characteristic may indicate the presence of anti-sperm antibodies?

Clumps of motile sperm

What temperature is ideal for holding a semen sample until time of testing?

37C

What causes a semen sample to normally liquefy after 30 minutes?

Prostate enzymes break down fluid

What condition is consistent with a semen pH of 8.5?

Infection

On a semen motility study, on what other characteristic are sperm graded besides speed?

Direction; should exhibit forward progressive motion

Before performing a sperm count, what do you use to dilute the sample, and what is the standard dilution?

Sodium bicarbonate; 1:20

What percent of sperm should be motile to be considered normal?

50% or more

What is a normal sperm count per mL?

20-160 million

If 42 sperm were counted in 5 RBC squares of a standard hemocytometer, what is the sperm count per mL?

42 million

15 million sperm per mL were counted in a 3.5 ml sample. What is the total sperm count?

52.5 million

What is a spermatid?

Immature sperm