NHA Certified Phlebotomy Technician (CPT)Collection RoutineMedium
A phlebotomy technician is preparing to collect a blood specimen for a routine chemistry panel, including liver function tests (LFTs). Which of the following tubes is most appropriate for this collection?
- ALavender top (EDTA)
- BLight blue top (Sodium Citrate)
- CGreen top (Heparin)
- DYellow top (SPS)
Show answer & explanationAnswer & explanation
Correct answer: C. Green top (Heparin)
Routine chemistry panels, including liver function tests, typically require serum or plasma. Green top tubes contain heparin, an anticoagulant that yields plasma, which is suitable for most chemistry tests and allows for faster turnaround times compared to serum tubes.
Why the other options are wrong
- A. Lavender top tubes contain EDTA and are used for hematology tests (e.g., CBC), not routine chemistry.
- B. Light blue top tubes contain sodium citrate and are used for coagulation studies (e.g., PT/INR, PTT).
- D. Yellow top tubes with SPS are primarily used for blood cultures, not routine chemistry.
Routine Chemistry Tube
The specific blood collection tube type used for various common chemistry tests, often containing an anticoagulant to yield plasma or a clot activator to yield serum.
- Common chemistry tests include electrolytes, glucose, LFTs, kidney function.
- Green (heparin) or Gold/Red SST (serum separator) are typical choices.
- Heparin prevents clotting, yielding plasma.
- SSTs contain a clot activator and gel separator, yielding serum.
Memory trick: RED LIGHT GREEN LAVENDER GREY: Remember Each Different Lab's Great List.