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

Sodium citrate for coagulation profiles

Answer

Lithium heparin for chemistry panels

Answer

Sodium fluoride for glucose testing

Question 2

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

Accepted Answer

30 minutes

Answer

15 minutes

Answer

60 minutes

Answer

4 hours

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

Urine color changes rapidly

Answer

Specific gravity increases over time

Answer

The pH always becomes more acidic

Question 4

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

Accepted Answer

10% neutral buffered formalin

Answer

70% ethanol

Answer

Normal saline

Answer

Bouin's solution

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

Leave at room temperature

Answer

Freeze at -20 degrees C immediately

Answer

Place in direct sunlight

Question 6

What does hemolysis in a blood sample indicate and how does it affect results?

Accepted Answer

Red blood cells have ruptured, causing false elevations in potassium, AST, and LDH

Answer

Bacterial infection with no effect on results

Answer

Correct collection with more accurate results

Answer

Elevated white blood cells requiring sample discard