Chemistry Final Exam (Exam 2-4)

A patient presents with chest pain described as an eight out of ten on a standardized pain scale. The patient has a history of chronic coronary syndrome but his nitroglycerin did not relieve the symptoms. The pain started approximately 3 hours ago. A point of care assay showed a myoglobin result of 174ng/mL (reference range: 0-85 ng/mL) and a cTnI of 0.05 ug/L. An EKG demonstrates no apparent abnormalities.What will most likely happen to the cTnI result within the next 24 hours?

Increase

The most common enzyme deficiency found in congenital adrenal hyperplasia patients is:

21-hydroxylase

A 72-year-old patient with a 15 year history of chronic coronary syndrome reports to a local emergency department. He state that he has found himself out of breath and has a persistent cough. He also complains of easy fatigue. Physical exam is unremarkable except for a resting pulse rate of 110 beats per minute. The emergency room physician orders a BMP, BNP, and cTnI. This patient probably has:

Left ventricular failure.

A patient with Cushing's Syndrome has a 8AM cortisol collected. The result was 31.2 ug/dL (Reference Range: 4.6-20.6 ug/dL). Her physician wants an 8PM cortisol result. The most likely result for this specimen would be:

29.1 ug/dL

A patient presents with chest pain described as an eight out of ten on a standardized pain scale. The patient has a history of chronic coronary syndrome but his nitroglycerin did not relieve the symptoms. The pain started approximately 3 hours ago. A point of care assay showed a myoglobin result of 174ng/mL (reference range: 0-85 ng/mL) and a cTnI of 0.05 ug/L. An EKG demonstrates no apparent abnormalities.What will most likely happen to the myoglobin result 24 hours after the initial point of care results?

Decrease

What condition will cause the following results?

TSH 15.3 0.4-4.5 mIU/L

fT4 0.2 0.8-2.4ng/dL

Thyroperoxidase Autoantibody Present

Hashimoto's thyroiditis

A patient has a TSH and free T4 test performed. Results are as follows:

TSH <0.2 0.4-4.5 mIU/L

fT4 2.1 0.8-2.4 ng/dL

What is the next best test that should be ordered?

Total T3

What patient condition will cause a decrease in the B-natriuretic peptide (BNP) levels?

Obesity

The ACEP guidelines state that a BNP greater than ___ is the cut point that positively identifies heart failure in normal weight patients with no kidney disease.

500 pg/mL

A medical laboratory scientist who has worked night shift for 5 years has recently been experiencing weight gain in the face and abdomen and fatigue. Her physician orders a BMP, TSH, and 8AM cortisol level. The physician calls and asks your opinion on if any other tests could be ordered. What is the next best course of action?

Request that a second cortisol be collected but that the sample be collected at 8PM on this particular patient.

A symptomatic 35-year-old female patient is found to have a prolactin level of 210ng/mL. Repeat testing shows her level to be a 205 ng/mL. The next best step to determine the cause of her elevated prolactin level is:

Perform a urine pregnancy test since none had been completed to date.

A 33-year-old patient presents with polyuria and the physician orders a saline infusion test. During the test the patient's plasma osmolality was a 310 mOsm/kg (Reference Range: 275-295 mOsm/kg). A subsequent water deprivation test was ordered. The patient's urine osmolality during the water deprivation test was 410 mOsm/kg (Reference Range: 500-850 mOsm/kg) after eight hours of no water. Two hours after administration of synthetic ADH, the patient's urine osmolality was measured at 625 mOsm/kg. What is the patient's diagnosis?

Central Diabetes Insipidus

What TnI results value is considered the lowest threshold of the WHO equivalent of an AMI regardless of symptoms?

0.50 ug/L

A patient presents with chest pain to a local emergency department. The patient has no history of chest pain, is panic stricken, and demonstrating excessive sweating and anxiety. The pain started approximately 6 hours ago and has gotten better after deep breathing. A point of care assay showed a myoglobin result of 72 ng/mL (reference range: 0-85 ng/mL) and a cTnI of 0.03 ug/L. An EKG demonstrates no apparent abnormalities.What is the patient's most likely diagnosis?

Stable angina

Which of the following is NOT one of the physiological compensatory mechanisms seen in patients with heart failure?

Cardiac atrophy and remodeling

What is the most likely serum calcium level for a patient with hyperparathyroidism?(Reference range: 8.5-10.2 mg/dL)

11.5 mg/dL

A patient presents with chest pain described as an eight out of ten on a standardized pain scale. The patient has a history of chronic coronary syndrome but his nitroglycerin did not relieve the symptoms. The pain started approximately 3 hours ago. A point of care assay showed a myoglobin result of 174ng/mL (reference range: 0-85 ng/mL) and a cTnI of 0.05 ug/L. An EKG demonstrates no apparent abnormalities.What is the patient's most likely diagnosis?

NSTEMI

A patient with secondary adrenal insufficiency undergoes an ACTH Stimulation test. The baseline cortisol at 8AM was measured at 2.1 ug/dL. What is the most likely cortisol level for this patient at the end of the functional study (six hours after synthetic ACTH infusion)?

23.4 ug/dL

What statement is TRUE about a patient with tertiary hypothyroidism?

The free T4 will be decreased

A 43-year-old patient presents complaining that they have experienced chest pain over the past 12 hours. The patient states that they had run a half-marathon two days prior and had been experiencing leg pain associated with the run. A stat point-of-care troponin T assay was ordered and the result was 0.03 ng/mL (reference range: <0.01 ng/mL). The patient was admitted to observation due to the elevated result. Serial troponin-I levels were ordered and sent to the main laboratory every 4 hours and all results were verified at 0.03ug/L. The patient was eventually discharged after 16 hours in observation with no significant cardiac events occurring. Why did the patient's point of care result warrant admission to the observation unit while follow-up collections led to their discharge?

The patient's muscle fatigue caused elevations in the point of care test. The assay run in the laboratory is more specific to cardiac damage

What cardiac biomarker(s) is/are commonly altered by the presence of hemolysis?

Troponin-I and Total Creatinine Kinase

Which of the following patients is at highest risk for coronary heart disease? (Reference Ranges: LDL<100mg/dL, HDL: 40-80mg/dL)

HDL: 35 mg/dL, LDL: 212 mg/dL

What description below would make the most ideal biomarker for AMI?

Small molecules from the myocardium that are quickly and completely released based upon the size of the infarction and remain elevated for 3-6 days

A patient is lethargic, frequently complains of cold sensations, and has gained significant weight over the last several months. A TSH found to be low and their thyroid hormone level is also found to be low. The patient is infused with thyrotropin releasing hormone and the TSH level increased after this infusion. This would be considered a ____ form of hypothyroidism.

Tertiary

A patient presents with chest pain to a local emergency department. The patient has no history of chest pain, is panic stricken, and demonstrating excessive sweating and anxiety. The pain started approximately 6 hours ago and has gotten better after deep breathing. A point of care assay showed a myoglobin result of 72 ng/mL (reference range: 0-85 ng/mL) and a cTnI of 0.03 ug/L. An EKG demonstrates no apparent abnormalities.What would this patient's Relative CK-MB index most likely be?

Normal

Which of the following statements correctly relates NT-proBNP and BNP?

NT-proBNP has a longer half-life and is less biologically active than BNP

Which of the following statements is true of natriuretic peptides?

Decrease renal sodium excretion. Decreases thirst reflex.

Which of the following is cause a false positive/elevation in most Troponin-I assays?

Heterophile antibodies

A patient with acromegaly will see a/n _____ growth hormone level after a 2 hour oral glucose tolerance test.

Increased

A patient complains of frequent urination and nocturia. Her urine output is found to be 3.1L/day. What is/are the appropriate follow-up step(s) to recommend?

Check the urine sample for glucosuria. Measure the patient's plasma osmolality. Perform a saline infusion test.

A patient who presents with weakness, fatigue, and who lab results demonstrate a hyperklalemia and hyponatremia, what test should be done?

ACTH stimulation test.

A patient who has presented with polyuria and a substantial decrease in plasma osmolality, which test should be done?

Saline infusion test/

A 52-year old patient who recent join point, enlargement of their feet, and an elevated grtowth hormone level. What test should be done?

Oral glucose tolerance test.

A patient who has gained weight in the face, abdomen, and upper back whose cortisol level is consistently elevated. What test should be done?

Dexamethasone suppression test.

A patient with cold intolerance and sudden weight gain whose thyroid hormone and free thyroxine were low. What test should be done?

TRH stimulation test.

Troponin returns to normal ______ days after infarction.

4 days

You are the chemistry MLS and are approached about a patient who presents with a mild anemia that has recently developed. The patient is a 45-year-old female with a hemoglobin of 10.1 g/dL and a MCV of 72 fL (microcytic anemia). You are asked what chemistry test would be the most helpful next choice in this scenario. What would your response be?

Ferritin

Which of the following would cause a secondary porphyria?

lead poisoning and iron deficiency anemia.

The biosynthesis of heme begins with which two compounds?

Glycine and Succinyl CoA

What form of iron is most readily absorbed in the small intestines?

Ferrous

The amount of iron transferrin can carry is the:

Total Iron Binding Capacity

A patient is seen in a local emergency department for a fever and chills. Results from their basic metabolic panel on a plasma sample revealed a potassium of 9.2 mEq/L and a total calcium of 0.2 mg/dL. What is the best course of action?

Determine the anticoagulant used

What statement is true of the relationship between pH and free, ionized calcium?

An acidic pH causes more calcium to be in its free, ionized form. An alkaline pH causes less calcium to be in free, ionized form.

The kidneys convert 25-hydroxy Vitamin D3 into ____.

1, 25- dihydroxy Vitamin D3

Multiple myeloma is a plasma cell dyscrasia where malignant plasma cells produce abnormal antibodies that often breakdown osseous tissue. This would cause a/n:

Humeral hypercalcemia

What method is used to determine free calcium levels?

Ion Selective Electrode method

A patient has a low phosphorus level. What diagnosis would correlate to this result?

Chronic Vomiting and Diarrhea

What vitamin can reduce platelet aggregation when in the body at toxic levels?

Vitamin E

What Vitamin's bioavailability is assessed using the prothrombin time clotting test?

Vitamin K

Deficiencies of ____ often produces nightblindness.

Vitamin A

A deficiency of ____ will cause Beri Beri.

Thiamin

A deficiency of ___ will lead to bone fragility, joint pain, muscle degeneration, rough skin, microcytic anemia, and depression

Vitamin C

A toxic level of ___ is associated with a dysfunction in bone remodeling and an elevated risk of Alzheimer's disease and other neurological complications

Aluminum

A deficiency of ____ is associated with megaloblastic anemia.

Cobalt

What essential trace element is involved in glucose metabolism?

Chromium

To avoid dental caries, an individual should take a/n ___ supplement.

Fluorine

Digoxin:

Alters cardiac contractility.

Phenytoin:

Helps block seizure activity.

Sirolimus:

Suppresses immune system function.

Vancomycin:

Inhibits growth of gram positive organisms.

Lithium:

Helps patients with various mood disorders.

Distribution of drug:

Free fraction of drug that can diffuse into interstitial space.

Absorption of drug:

Rate at which drug leaves site of administration.

Biotransformation:

Chemical alterations of the drug that aid in its elimination.

Pancreatic best tumor marker:

CA 19-9

Ovarian cancer best tumor marker:

CA 125

Bladder cancer best tumor marker:

Nuclear matrix protein 22

Breast cancer best tumor marker:

CA 15-3

Colorectal cancer best tumor marker:

CEA

Which of the following does not influence the absorption of a drug?

availability of cytochrome P450 in the liver

What tumor marker is derived from the Lewis A blood group?

CA 19-9 and CA50

Salicylate (Aspirin) results in a reduction in total carbon dioxide. What type of acid/base imbalance results from this?

Metabolic acidosis

What toxic compound routinely measured by gas chromatography is oxidized to formaldehyde and formic acid that directly causes tissue injury?

Methanol

What cell type is directly impacted by ingestion of salicylates through its inhibition of prostaglandin synthesis?

Thrombocytes

Screening test for drugs of abuse routinely uses what method? (select all that apply)

Colorimetric and immunoassay.

A serum PSA is used for all of the following EXCEPT

Confirming Diagnosis

What enzyme(s) is often a useful tumor marker of lymphoma, leukemia, and liver cancers?

Lactate dehydrogenase

A physician asks you about a patient who tested positive for a biomarker and she wants to know what the percent likelihood the patient actually has the disease based upon that positive result.. What statistic would be most beneficial?

Positive predictive value

CA-125 is expressed by which of the following tissues?

Ovarian epithelial cells

A drug has a half-life of 12 hours. After 48 hours since the patient was at peak therapeutic levels, the patient's level of the drug is 15 ug/mL. What was the peak therapeutic level?

240 ug/mL

First-pass effect occurs in which organ of the human body?

liver

A ROC curve is used to visually assess the ____ of an assay at various clinically meaningful cut-points.

accuracy

A ROC curve is constructed and the AUC is found to be 0.72. Based upon commonly used convention, this would be considered a _____ diagnostic assay.

fair

Warfarin is a drug used to reduce the risk of inappropriate blood clots. It undergoes a series of biotransformations once absorbed. Some individuals have a genetic propensity to overexpress the gene responsible for the Phase II Reactions involved in this biotransformation and create too much of the enzyme responsible for these reactions. What impact will this increase in phase II reactions have on the dosing of the drug?

The patient will need higher doses to achieve the MEC

A patient is found to have prostate cancer. Besides their elevated PSA, the physician notes an increase in the alkaline phosphatase and is concerned about metastasis of the malignancy. What secondary cancer should be of concern if metastasis did occur? (select all that apply)

Bone cancer and liver cancer.

A drug has a half life of 6 hours. The peak concentration of the drug was 600 mg/mL. What is the expected concentration after 36 hours?

9 mg/mL

Which of the following patients will experience a prolonged elimination half-life of a drug? (select all that apply)

A patient with an elevated blood urea nitrogen level. A patient with an elevated total bilirubin and elevated direct bilirubin.

Measuring serum HER-2/neu is clinically used for which of the following:

Providing prognosis and predictive model to individual cases of breast cancer.

A physician orders a trough level of digoxin on a patient. The physician is trying to assess:

CMin

How to calculate immunoassay sensitivity:

TP / TP+FN

How to calculate specificity of immunoassay:

TN / TN+FP

How to calculate positive predictive value:

TP / TP + FP

How to calculate negative predictive value:

TN / TN+FN