Laboratory Procedures Flashcards

Which test is used to screen for colorectal cancer by detecting hidden blood in stool?

Answer: Fecal occult blood test (FOBT)

The fecal occult blood test (FOBT) detects blood in stool not visible to the naked eye, serving as an early screening tool for colorectal polyps or cancer.

Hematocrit measures:

Answer: The percentage of blood volume occupied by red blood cells

Hematocrit (Hct or PCV) is the percentage of total blood volume that is red blood cells, normally 37–52% in adults depending on sex.

A patient's serum potassium level is reported as 6.2 mEq/L. This value indicates:

Answer: Hyperkalemia (elevated potassium)

Normal serum potassium is 3.5–5.0 mEq/L. A value of 6.2 mEq/L indicates hyperkalemia, which can cause life-threatening cardiac dysrhythmias.

The prothrombin time (PT) test evaluates which coagulation pathway?

Answer: Extrinsic pathway (factor VII) and common pathway (factors I, II, V, X)

PT/INR tests the extrinsic coagulation pathway (tissue factor + factor VII) and the common pathway (factors X, V, II, fibrinogen).

When a laboratory result is flagged as a 'critical value,' the medical assistant should:

Answer: Immediately notify the responsible physician or provider and document the notification

Critical values represent life-threatening results requiring immediate provider notification. TJC mandates that critical values be communicated to the responsible caregiver within a defined timeframe.

Quality control (QC) in a physician office laboratory is performed to:

Answer: Ensure that test results are accurate and reliable before patient results are reported

QC testing uses known-value control samples to verify that the testing system is performing correctly before patient results are released.