18/12/2025
🧪 Blood Collection Tubes & Their Common Laboratory Uses
Correct blood tube selection is essential for accurate laboratory results. Each tube contains a specific additive that determines which tests can be reliably performed.
🔵 Light Blue (Sodium Citrate)
Used for coagulation studies including PT, INR, aPTT, D-dimer, and fibrinogen. Proper tube filling is critical to maintain the correct blood-to-anticoagulant ratio.
🔴 Red (Plain / Clot Activator)
Provides serum for hormone assays, drug level monitoring, toxicology screening, and antibody or serology testing.
🟡 Gold (Serum Separator Tube – SST)
Used for biochemical and immunoassay tests such as urea, creatinine, liver function tests, lipid profile, and thyroid function tests.
🟢 Green (Heparin)
Provides plasma for electrolyte estimation, cardiac markers, and routine chemistry tests. Preferred for electrolyte analysis.
🟣 Lavender (EDTA)
Used for hematology investigations including complete blood count (CBC), HbA1c estimation, and peripheral smear examination.
🩷 Pink (EDTA – Blood Bank)
Specifically used in transfusion medicine for blood grouping, cross-matching, and type-and-screen testing.
⚪ Grey (Fluoride Oxalate)
Inhibits glycolysis and is used for glucose estimation, blood alcohol levels, and lactate measurement.
🦠 Blood Culture Bottles (Aerobic & Anaerobic)
Used to detect bloodstream infections and should be collected before antibiotic administration using strict aseptic technique.
📌 Accurate tube selection prevents sample errors, avoids repeat testing, and ensures reliable patient care.
