I. Application Scenarios

Red-top vacuum blood collection tubes are primarily classified into two types with distinct purposes:

1. Additive-Free Plain Tube (Classic Red Top):

   • Contains no anticoagulants or clot activators; relies on natural blood coagulation to separate serum.

   • Suitable for: Serum biochemistry (liver/kidney function, cardiac enzymes, electrolytes), thyroid function, tumor markers, immunology (e.g., syphilis, HBV quantification), blood bank cross-matching.

2. Clot Activator Tube (Red or Orange-Red Top ):

   • Interior coated with clot activators to accelerate coagulation (5–15 minutes).

   • Suitable for: Emergency biochemistry, rapid serological immunology, pharmacokinetic studies, and other time-sensitive tests.

II. Product Highlights (Comparative Table)

III. Usage Precautions

1. Sample Handling Protocol:

   • Additive-Free Tube: After collection, let stand upright (no mixing). Incubate at 37°C for ≥30 minutes to accelerate clotting before centrifugation.

   • Clot Activator Tube: Invert gently 5–8 times immediately after collection (ensuring contact with activator). Let stand upright for 15–20 minutes before centrifugation.

   • ❗ Critical: Inadequate mixing or insufficient standing time may cause "fibrin microclots" (jelly-like serum), affecting test accuracy (e.g., estradiol, Down syndrome screening).

2. General Contraindications:

   • Never transfer blood from other tubes into red-top tubes to avoid cross-contamination.

   • Fill to the nominal volume (e.g., 6ml/10ml) to ensure proper serum yield.

   • Avoid vigorous shaking to prevent hemolysis.

IV. Troubleshooting

V. Basic Parameters

VI. Summary

Red-top vacuum blood collection tubes are indispensable for biochemistry and immunology testing due to their additive-free purity (plain tubes) and rapid separation capability (clot activator tubes). Strict adherence to protocols—distinguishing tube types, proper mixing, and standing time—is essential to ensure serum integrity. Clot activator tubes excel in emergencies, while additive-free tubes remain the gold standard for precision testing and long-term storage.