Order of Draw Tubes, Additives, Inversions and Departments

1. Order of Draw: Preventing Cross-Contamination

The specific order in which blood collection tubes are drawn helps prevent additive cross-contamination, which can alter test results.

2. Tube Types, Additives, Inversions, and Common Tests

  1. Blood Culture Bottles or Tubes (Sterile)

    • Additive: Culture media (aerobic and anaerobic)

    • Inversions: 8-10 times (to mix blood with media)

    • Common Tests: Blood cultures (detection of bacteremia/septicemia)

    • Department: Microbiology

  2. Light Blue Top Tube (Coagulation Tube)

    • Additive: Sodium Citrate (anticoagulant that binds calcium)

    • Inversions: 3-4 times (to ensure proper mixing of anticoagulant)

    • Specimen: Plasma

    • Common Tests: Prothrombin Time (PT), PTT (Partial Thromboplastin Time), Activated Partial Thromboplastin Time (aPTT), Fibrinogen, D-Dimer

    • Department: Coagulation

  3. Red Top Tube (No Additive)

    • Additive: No additive (glass tubes contain no additive; plastic tubes may contain clot activators like silica particles, but are still considered "no additive" for this purpose)

    • Inversions: 0 times (if glass) or 5 times (if plastic with clot activator)

    • Specimen: Serum

    • Common Tests: Drug levels, Type and Screen, Crossmatch (if plastic), Chemistry tests requiring serum (e.g., some therapeutic drug monitoring)

    • Department: Blood Bank, Chemistry

  4. Gold/Tiger Top Tube (SST - Serum Separator Tube)

    • Additive: Gel separator and clot activator (silica particles)

    • Inversions: 5-8 times (to activate clotting)

    • Specimen: Serum

    • Common Tests: Comprehensive Metabolic Panel (CMP), Basic Metabolic Panel (BMP), Liver Function Tests (LFTs), Lipid Panel, Thyroid Function Tests, Hormone studies, most routine chemistry tests

    • Department: Chemistry

  5. Green Top Tube (Heparin Tube)

    • Additive: Heparin (Sodium, Lithium, or Ammonium Heparin - anticoagulant that inhibits thrombin)

    • Inversions: 8-10 times (to ensure proper mixing of anticoagulant)

    • Specimen: Plasma

    • Common Tests: Ammonia, Carboxyhemoglobin, STAT Chemistry tests (e.g., electrolytes, glucose, cardiac enzymes when rapid results are needed).

    • Department: Chemistry

  6. Lavender/Purple Top Tube (EDTA Tube)

    • Additive: EDTA (Ethylenediaminetetraacetic acid - anticoagulant that binds calcium)

    • Inversions: 8-10 times (to prevent microclot formation)

    • Specimen: Whole Blood

    • Common Tests: Complete Blood Count (CBC), Hemoglobin A1c (HbA1c), Erythrocyte Sedimentation Rate (ESR), Platelet count, Blood Typing

    • Department: Hematology, Blood Bank

  7. Pink Top Tube (EDTA Tube - specialized for Blood Bank)

    • Additive: EDTA K2 (specifically formulated for blood bank requirements)

    • Inversions: 8-10 times

    • Specimen: Whole Blood

    • Common Tests: Type and Screen, Crossmatch, Blood Typing

    • Department: Blood Bank

  8. Gray Top Tube (Glucose Tube)

    • Additive: Sodium Fluoride (antiglycolytic agent) and Potassium Oxalate (anticoagulant)

    • Inversions: 8-10 times (to ensure proper mixing and prevent glycolysis)

    • Specimen: Plasma

    • Common Tests: Glucose (fasting, random, 2-hour postprandial), Glucose Tolerance Test (GTT), Lactic Acid (on ice), Alcohol levels

    • Department: Chemistry

3. Importance of Inversion

  • Proper inversion ensures that the additive fully mixes with the blood sample. Insufficient mixing can lead to clot formation in anticoagulant tubes or incomplete clotting in tubes with clot activators, leading to inaccurate test results or sample rejection.

4. Key Considerations

  • Tube Fill Volume: Most tubes require a specific fill volume to ensure the correct blood-to-additive ratio. Underfilling or overfilling can lead to inaccurate results.

  • Needle Gauge and Site Selection: Appropriate needle gauge and venipuncture site selection are crucial for successful blood collection and patient comfort.

  • Patient Identification: Always verify patient identity using at least two identifiers before blood collection to prevent errors.