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Module 1: Fundamentals: Practice Questions

1. (F1) An urban free clinic in a large city offers testing for infection with syphilis. The clinic uses a screening test designed to obtain maximum sensitivity, followed by a second test performed before results are reported. Which of the following outcomes is most likely to characterize this screening test?

A. Increased false positive tests

B. Decreased false positive tests

C. Increased false negative tests

D. Decreased false negative tests

2. (F2) A 50-year-old healthy man has a serum alanine aminotransferase (ALT) test. The value is 21 U/L and the normal range is 8 - 20 U/L. What is the probability that his result falls outside of the normal range?

A. 1 in 20

B. 1 in 10

C. 1 in 4

D. 1 in 2

3. (F6) A 62-year-old woman with atrial fibrillation is taking warfarin. On her latest visit, she reports no problems. A blood specimen is obtained for prothrombin time. How should this test be ordered?

A. Routine turnaround time

B. Stat turnaround time

C. Report abnormal value to the health department

D. Report critical value electronically

E. Draw via phlebotomy into a red top tube

F. Draw via phelbotomy into a purple top tube

4. (F7) An electrolyte panel is obtained for an adult patient with gastroenteritis and diarrhea. Results show sodium 118 mmol/L, potassium 3.1 mmol/L, chloride 88 mmol/L, and HCO3 23 mmol/L. A serum osmolality is then obtained and shows 290 mOsm/kg. Which of the following is the most likely explanation for these findings?

A. Analytical error with instrumentation in the laboratory

B. Concurrent diabetes insipidus with dehydration

C. Fluid overload from intravenous administration of saline

D. Hemolysis in obtaining specimens during phlebotomy

E. Lipemic interference with electrolyte measurement

5. (F10) A series of point-of-care glucose measurements from a hospital ward yields glucose values that are all much lower than the corresponding values from specimens drawn and sent to the hospital laboratory. In which of the following phases of testing is the causative problem most likely to be?

A. Preanalytical

B. Analytical

C. Postanalytical

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