Specimen Collection and Pre-Analytical Processing Flashcards

Grossly lipemic serum is most likely to interfere with which method?

Answer: Spectrophotometric assays because of light scattering

Lipid particles scatter light and interfere with photometric measurements.

A patient had a left mastectomy with lymph node removal. Where should venipuncture be done?

Answer: The right arm

The side of a mastectomy with node removal is avoided because of lymphedema and infection risk.

An EDTA specimen shows a falsely low platelet count, and the smear shows platelet clumps around neutrophils. What is the best next step?

Answer: Recollect in a sodium citrate tube and correct the count for dilution

EDTA-induced platelet satellitism is usually resolved by a citrate tube, with the count corrected for the 1:9 dilution.

Which situation requires a documented chain of custody?

Answer: Forensic blood alcohol or workplace drug testing

Legal specimens need documented chain of custody so results are admissible as evidence.

For a legal blood alcohol draw, which skin antiseptic is appropriate?

Answer: Non-alcohol cleanser such as povidone-iodine or benzalkonium

Alcohol antiseptics may contaminate the specimen and challenge a legal blood alcohol result.

For best results, a semen specimen for fertility analysis should be delivered to the lab how?

Answer: Within 1 hour, kept near body temperature

Motility drops with time and cold, so specimens are kept warm and tested within about an hour.

A gel separator serum tube is centrifuged before it fully clots. What problem is most likely?

Answer: Latent fibrin strands that can clog analyzer probes

Spinning before full clotting leaves fibrin forming in the serum, which can clog probes and cause errors.