Classification Of Blood Collection Tubes

1. Blood Culture Tubes (Yellow/Yellow-Black Striped)

Priority in collection to avoid contamination. Contain sodium polyanethole sulfonate (SPS) (anticoagulant) and microbial growth media. Used exclusively for detecting bloodstream infections by cultivating aerobes, anaerobes, or fungi.

2. Coagulation Tubes (Light Blue Top)

Contain 3.2% sodium citrate (anticoagulant, binds calcium). For coagulation tests (PT, APTT, fibrinogen). Must be filled to specified volume to maintain accurate anticoagulant-blood ratio.

3. Serum Tubes

- Red Top: No additives; blood clots naturally. For routine biochemistry, immunology, and blood bank tests.

- Gold Top (SST): Clot activator + separation gel (forms serum-cell barrier). Stabilizes serum for 48h; ideal for emergency or serialized tests.

- Orange Top: Fast-acting clot activator; clots blood in 5min. For urgent serum tests.

4. Anticoagulant Tubes (Plasma/Whole Blood)

- Purple/Lavender Top: EDTA (chelates calcium). Preserves cell morphology; for hematology tests (CBC, blood smear).

- Green Top: Heparin (inhibits thrombin). Yields plasma; lithium heparin for biochemistry, sodium heparin for lithium tests. Light green top (PST) adds separation gel for rapid plasma separation.

- Black Top: Sodium citrate. Dedicated to erythrocyte sedimentation rate (ESR) tests.

5. Glucose Preservation Tubes (Light Grey Top)

Sodium fluoride (antiglycolytic agent) + potassium oxalate (anticoagulant). Stabilizes glucose for up to 5 days; for fasting blood glucose and tolerance tests.

6. Special-Purpose Tubes (Pale Yellow Top)

Contain acid-citrate-dextrose (ACD) to preserve cell/nucleic acid integrity. Used for HLA typing, paternity testing, and DNA research.

Proper selection and use of these tubes, along with following collection protocols, are critical for test accuracy.