CVA Laboratory Sample Handling 2

Question 1

What anticoagulant does a purple/lavender top tube contain and what is it primarily used for?

Accepted Answer

EDTA for complete blood counts (CBC)

Answer

Purple/lavender top tubes contain EDTA which preserves cell morphology and prevents clotting, making them ideal for CBCs.

Question 2

What is the maximum recommended time between blood collection and serum separation?

Accepted Answer

30 minutes

Answer

Serum should be separated from the clot within 30 minutes to prevent falsely elevated potassium, phosphorus, and other analytes from cellular leakage.

Question 3

Why must a urinalysis sample be analyzed within 30 minutes of collection?

Accepted Answer

Crystals may form artificially, bacteria multiply, and cells degrade

Answer

Delayed analysis leads to bacteria proliferation, artificial crystal formation or dissolution, and cell lysis, all producing inaccurate results.

Question 4

Which fixative is standard for preserving tissue biopsy samples for histopathology?

Accepted Answer

10% neutral buffered formalin

Answer

10% neutral buffered formalin is the universal standard for histopathology, preserving tissue architecture and being compatible with most staining protocols.

Question 5

What is the recommended storage method for fecal samples if analysis will be delayed more than 2 hours?

Accepted Answer

Refrigerate at 4 degrees C or mix with formalin preservative

Answer

Refrigeration slows parasite egg development and larval hatching. Formalin preservative permanently stabilizes eggs and larvae.

(CVA) Certified Veterinary Assistant Practice Test

(CVA) Certified Veterinary Assistant Practice Test

CVA Laboratory Sample Handling 2