Laboratory Sample Handling Flashcards
6 cards from real CVA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Laboratory Sample Handling flashcards as text
What anticoagulant does a purple/lavender top tube contain and what is it primarily used for?
Answer: EDTA for complete blood counts (CBC)
Purple/lavender top tubes contain EDTA which preserves cell morphology and prevents clotting, making them ideal for CBCs.
What is the maximum recommended time between blood collection and serum separation?
Answer: 30 minutes
Serum should be separated from the clot within 30 minutes to prevent falsely elevated potassium, phosphorus, and other analytes from cellular leakage.
Why must a urinalysis sample be analyzed within 30 minutes of collection?
Answer: Crystals may form artificially, bacteria multiply, and cells degrade
Delayed analysis leads to bacteria proliferation, artificial crystal formation or dissolution, and cell lysis, all producing inaccurate results.
Which fixative is standard for preserving tissue biopsy samples for histopathology?
Answer: 10% neutral buffered formalin
10% neutral buffered formalin is the universal standard for histopathology, preserving tissue architecture and being compatible with most staining protocols.
What is the recommended storage method for fecal samples if analysis will be delayed more than 2 hours?
Answer: Refrigerate at 4 degrees C or mix with formalin preservative
Refrigeration slows parasite egg development and larval hatching. Formalin preservative permanently stabilizes eggs and larvae.
What does hemolysis in a blood sample indicate and how does it affect results?
Answer: Red blood cells have ruptured, causing false elevations in potassium, AST, and LDH
Hemolysis occurs when RBCs rupture, releasing intracellular contents that falsely elevate potassium, AST, LDH, and phosphorus.