Gel Separator
Forms a solid barrier after centrifugation.
Isolates serum from blood cells → Prevents cellular contamination (e.g., false ↑K⁺/LDH).
Clot Activator
Silica particles: Activate Factor XII → Accelerate clotting to 15–30 min.
Thrombin: Catalyzes fibrin formation in <5 min (emergency use).
Workflow: Blood draw → 5 gentle inversions → 30 min clotting → Centrifuge → Direct automated analysis.
Efficiency: Processes 500+ samples/day (vs. 200 with manual separation).
Potassium (K⁺): Prevents RBC lysis → ↓ False hyperkalemia (error rate: 8% → 0.5%).
LDH: Blocks cellular LDH release → ↑ Myocardial infarction diagnostic accuracy.
Glucose: Inhibits glycolysis → <2% glucose loss after 2h RT storage (vs. >10% in plain tubes).
Thrombin-enhanced tubes: Cardiac markers (cTnI/CK-MB/Myo) results 45 min faster.
Impact: Reduces ER "door-to-balloon" time to <90 min (global standard).
Cost saving: Eliminates manual serum separation → Saves $200k/year (mid-size lab).
Quality: ISO 15189 compliance → Inter-lab QC pass rate 99.2% (vs. 93.5%).
Coagulation tests (PT/APTT): Use sodium citrate tubes (blue top).
Ammonia testing: Use heparin tubes + ice bath.
Trace elements (Zn/Cu): Use additive-free tubes.
Alert: Gel tubes for coagulation tests cause false ↓APTT → Risk of misdiagnosis!
Gold-standard tubes: BD SST™ (gold top), Greiner Vacuette® Z (yellow/black top).
Selection logic:
Emergency: Thrombin-enhanced gel tubes.
Routine: Silica gel tubes.
Special tests: Follow Clinical Specimen Collection Guidelines 3rd Ed.
Key innovation: Solves the "quality vs. speed" dilemma in serum testing.