CMLA Specimen Collection & Processing 2

Question 1

Which type of specimen typically requires transport on ice to preserve analyte integrity?

Accepted Answer

Ammonia, lactic acid, or arterial blood gas specimens

Answer

Ammonia, lactic acid, and arterial blood gases are labile analytes that continue to be metabolized by cells at room temperature; ice slows this process and preserves accurate results.

Question 2

What does hemolysis in a blood sample indicate, and which test result is most critically affected?

Accepted Answer

Rupture of red blood cells; most critically affects potassium levels

Answer

Hemolysis releases intracellular contents (particularly potassium) from red blood cells into the serum, falsely elevating serum potassium and several other analytes.

Question 3

What is the correct antiseptic used to prepare the skin site before drawing blood cultures?

Accepted Answer

Povidone-iodine or chlorhexidine gluconate scrub followed by 70% alcohol

Answer

Blood cultures require a two-step antiseptic preparation (povidone-iodine or chlorhexidine followed by alcohol) to reduce skin flora and minimize the risk of false-positive contamination.

Question 4

What is the proper handling procedure for a urine culture specimen once collected?

Accepted Answer

Refrigerate at 2–8°C and process within 2 hours, or within 24 hours if refrigerated

Answer

Urine culture specimens must be refrigerated at 2–8°C to inhibit bacterial overgrowth; they should be processed within 2 hours at room temperature or within 24 hours if refrigerated to ensure accurate colony counts.

Question 5

How many times should most anticoagulant blood tubes be gently inverted after collection, and why?

Accepted Answer

8–10 times, to thoroughly mix the additive with blood

Answer

Gentle inversion 8–10 times ensures the anticoagulant or additive is evenly distributed throughout the blood sample without causing hemolysis from vigorous shaking.

CMLA - Certified Lab Assistant Practice Test

CMLA - Certified Lab Assistant Practice Test

CMLA Specimen Collection & Processing 2