Clinical Pathology Flashcards

Which laboratory error type is detected by a Levey-Jennings chart showing a sudden shift of consecutive points on one side of the mean?

Answer: Systematic error

A sustained shift or trend on a Levey-Jennings chart indicates systematic error affecting accuracy.

Westgard rule 1-3s violation on quality control indicates that a single result exceeded:

Answer: Three standard deviations from the mean

The 1-3s rule flags a run when one control value falls outside three standard deviations of the mean.

Which specimen anticoagulant is required for most coagulation testing such as PT and PTT?

Answer: Sodium citrate

Sodium citrate (light blue top) is the standard anticoagulant for coagulation studies because it is reversible with calcium.

A newborn screen flags elevated 17-hydroxyprogesterone. This most strongly suggests:

Answer: Congenital adrenal hyperplasia

Elevated 17-hydroxyprogesterone is the marker for 21-hydroxylase deficiency causing congenital adrenal hyperplasia.

Which fecal test is most specific for lower gastrointestinal bleeding and not affected by dietary peroxidases?

Answer: Fecal immunochemical test (FIT)

FIT detects human globin and is unaffected by dietary peroxidases, making it more specific for lower GI bleeding.

A patient with megaloblastic anemia, hypersegmented neutrophils, and neurologic symptoms most likely has a deficiency of:

Answer: Vitamin B12

Vitamin B12 deficiency causes megaloblastic anemia with hypersegmented neutrophils plus neurologic deficits, unlike folate deficiency.

Which method is the reference standard for confirming an elevated point-of-care glucose in a critically ill patient?

Answer: Central laboratory plasma glucose by hexokinase

The hexokinase method on a central chemistry analyzer is the reference standard for confirming glucose values.