Specimen Processing and Handling Flashcards

What is the maximum time a whole blood specimen should sit before being centrifuged if serum is required?

Answer: 60 minutes

Whole blood specimens should be allowed to clot for 30–60 minutes before centrifugation; exceeding 2 hours can compromise analyte integrity, but 60 minutes is the standard upper threshold.

Which additive tube must NEVER be centrifuged?

Answer: EDTA (lavender)

EDTA tubes are collected for whole blood analysis (CBC); centrifuging them separates plasma, destroying the specimen's intended use.

A specimen labeled 'STAT' should be processed within how many minutes of collection?

Answer: 15 minutes

STAT specimens require processing within 15 minutes of collection to ensure rapid, accurate results for urgent clinical decisions.

When transporting a cold-sensitive specimen, which method is most appropriate?

Answer: Transport in ice slurry at 0–4°C

Cold-sensitive specimens such as ammonia, lactic acid, or ABGs must be transported in an ice slurry (0–4°C) to slow metabolic degradation.

Which of the following causes hemolysis in a blood specimen?

Answer: Forcing blood through a small-gauge needle rapidly

Forcing blood through a small-gauge needle or syringe at high velocity creates shear stress that ruptures red blood cells, causing hemolysis.

What does a hemolyzed specimen indicate when visually inspected?

Answer: Pink to red discoloration of serum or plasma

Hemolysis releases hemoglobin from red blood cells into the serum or plasma, producing a characteristic pink to red color.

A lipemic specimen appears:

Answer: Milky or cloudy white

Lipemia is caused by elevated triglycerides in the blood, giving serum or plasma a milky, turbid, or cloudy white appearance.