Specimen Processing & Handling — Phlebotomy Technician Practice Test

This Phlebotomy Technician Specimen Processing & Handling practice set has 44 practice questions based on the official exam materials, each with an instant explanation.

Sample questions

Three questions from the Specimen Processing & Handling bank with the correct answer and an explanation. The practice quiz above draws 30 questions at random from the same bank.

1. Before centrifuging a serum (red-top or gel/SST) tube, the specimen must first:

   • Be allowed to clot completely at room temperature — Correct answer
   • Be shaken vigorously to mix
   • Be frozen for 10 minutes
   • Be diluted with saline

   Explanation: A serum tube must be allowed to clot completely before centrifugation; spinning it too early produces a fibrin clot and poor serum separation. (Source: CLSI GP44)

   Handbook: Specimen Processing & Handling — Centrifugation

2. For a typical serum (red-top) tube, complete clotting before centrifugation takes about:

   • 30 to 60 minutes at room temperature — Correct answer
   • 2 to 3 minutes at room temperature
   • 24 hours refrigerated
   • 5 seconds after collection

   Explanation: A serum tube generally requires about 30 to 60 minutes at room temperature to clot completely before it is centrifuged. (Source: CLSI GP44)

   Handbook: Specimen Processing & Handling — Centrifugation

3. A gel-barrier (SST) tube generally requires about how long to clot before centrifugation?

   • About 30 minutes — Correct answer
   • About 5 minutes
   • About 4 hours
   • No clotting time is needed for SST tubes

   Explanation: A gel/SST tube typically needs about 30 minutes at room temperature to clot before it can be centrifuged. (Source: CLSI GP44)

   Handbook: Specimen Processing & Handling — Centrifugation