CMT Clinical Chemistry 5

Question 1

Two consecutive control results exceed +2 SD on the same side of the mean. This violates which Westgard rule, and what error does it indicate?

Accepted Answer

2-2s; systematic error

Answer

2-2s rejects a run when two consecutive controls exceed 2 SD on the same side, which signals systematic bias.

Question 2

According to Beer's law, absorbance is:

Accepted Answer

Directly proportional to concentration

Answer

A = abc, so absorbance increases linearly with concentration at a fixed path length.

Question 3

The Jaffe method for creatinine uses which reagent?

Accepted Answer

Alkaline picrate

Answer

Creatinine reacts with picrate in alkaline solution to form a red-orange complex.

Question 4

Increased conjugated bilirubin, positive urine bilirubin, and decreased urine urobilinogen most strongly suggest:

Accepted Answer

Biliary obstruction

Answer

Blockage stops bilirubin reaching the gut, so urobilinogen falls while water-soluble conjugated bilirubin spills into urine.

Question 5

Which handling requirement is most critical for a serum bilirubin specimen?

Accepted Answer

Protect from light

Answer

Light breaks down bilirubin and causes falsely low results.

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