I. Product Characteristics

EDTA blood collection tubes (purple cap) utilize dipotassium or tripotassium ethylenediaminetetraacetate (EDTA-K₂ or EDTA-K₃) as the core anticoagulant, featuring:

1. Precise Anticoagulation Mechanism: Chelates calcium ions (Ca²⁺) in blood to block thrombin activation, achieving complete anticoagulation while maximally preserving blood cell morphology.

2. Optimized Physical Design:

   • High-transparency PET plastic or glass tube with mechanical strength and light resistance;

   • Pre-filled precise anticoagulant dosage (1.5–2.2 mg EDTA/mL blood), vacuum accuracy ≤±5%.

3. Safety & Quality Control:

   • Gamma-irradiated sterilization (8–25 kGy), controlled endotoxin levels;

   • ISO13485/CE compliant; standardized purple cap for rapid identification.

II. Application Scenarios

Primarily for hematological testing, with specific applications:

Note: EDTA tubes cannot be used for electrolyte, trace element, or coagulation testing due to chelation interference.

III. Usage Protocol & Specifications

IV. Precautions

1. Anticoagulant Risks:

   • Overfill (>2.2 mg/mL): RBC shrinkage/platelet swelling → morphology distortion;

   • Underfill: Inadequate anticoagulation → microclots → instrument obstruction.

2. Sample Handling:

   • Do not reuse tubes or mix additives;

   • Blood volume ≤ labeled capacity (e.g., ≤5.5 mL for 5 mL tube).

3. Safety:

   • EDTA is corrosive; rinse skin/eyes immediately with water if contacted.

V. FAQs

1. EDTA-K₂ vs. EDTA-K₃?

   • Solubility: K₃ dissolves easier → liquid pre-filled tubes; K₂ → spray-dried plastic tubes;

   • Performance: Comparable anticoagulation, but K₃ excess may cause platelet satellitism (pseudothrombocytopenia).

2. Causes of Pseudothrombocytopenia? Solutions?

   • Causes: EDTA-induced platelet aggregation (~0.1% incidence) or neutrophil adhesion (satellitism);

   • Resolution: Recollect using sodium citrate tube.

3. Can tubes with microclots be used?
   → No. Microclots indicate anticoagulation failure → recollect with thorough mixing.

4. Suitable for glucose testing?
   → Compatible with sodium fluoride (2–4 mg/mL blood) to inhibit glycolysis; validate system compatibility.

Clinical Note: EDTA tubes remain the gold standard for CBC. For abnormal cases (e.g., suspected platelet disorders), parallel testing with alternative anticoagulants is recommended.