Purple Cap PET Glass EDTA Blood Collection Tube
1. Definition and Specifications
The Purple Cap tube is a vacuum blood collection tube designed for hematology testing. It features a PET (Polyethylene Terephthalate) outer layer for shatter resistance and an inner glass tube for sample integrity. The key additive is either K2 (dipotassium) or K3 (tripotassium) Ethylenediaminetetraacetic Acid (EDTA), which acts as an anticoagulant by chelating calcium.
2. Key Specifications
- Additive: K2EDTA or K3EDTA
- Draw Volume: Common sizes are 2mL, 3mL, 4mL, and 5mL.
- Blood-to-Anticoagulant Ratio: Precisely calibrated for accurate results.
- Closure: Purple rubber stopper and tamper-evident cap.
3. Key Technical Features
The PET shell provides superior mechanical strength, reducing breakage risks and ensuring safety. The inner glass maintains a stable environment for the sample. EDTA effectively prevents coagulation by inhibiting clotting factors, preserving cellular morphology for accurate analysis.
4. Primary Applications
- This tube is exclusively used for whole blood hematology tests, including:
- Complete Blood Count (CBC)
- Blood Smear Preparation
- Hemoglobin A1c (HbA1c) testing
- Erythrocyte Sedimentation Rate (ESR)
5. Critical Safety Notes
Invert the tube 8-10 times immediately after collection to ensure proper mixing with the anticoagulant. Failure to mix can lead to clot formation and sample rejection. Do not use for coagulation studies or chemistry tests.
6. Disposal Protocol
Dispose of as biohazardous waste. Tubes must be placed in a designated, puncture-proof sharps container after use to prevent needlestick injuries and cross-contamination, following institutional and regulatory guidelines.