Vacutainers

Vacutainers are evacuated blood collection tubes used in conjunction with a needle and holder to collect blood in a closed system. The vacuum inside the tube draws a precise volume of blood when the needle punctures the stopper, helping to standardize sample volumes and reduce contamination. They come in plastic or glass and are usually color-coded by cap and additive to indicate the intended test type.

Common varieties include: red top tubes, which may be plain or contain clot activators for serum collection; gold or tiger top tubes, which contain clot activator and gel for serum separation; purple or lavender top tubes containing EDTA for hematology and some chemistry tests; blue top tubes containing sodium citrate for coagulation studies; green top tubes containing heparin for plasma chemistry; and gray top tubes containing potassium oxalate and sodium fluoride for glucose testing. Some tubes also use gel separators to create a distinct serum or plasma layer after centrifugation.

In use, vacutainers are part of a phlebotomy system where the evacuated tube fills to its marked capacity. The blood is then mixed by gentle inversion, as appropriate for the additive, to ensure proper anticoagulation or clotting. The choice of tube depends on the required test panel, and some tests require serum rather than plasma.

Handling and storage practices include observing expiration dates, protecting light-sensitive additives when applicable, and proper labeling. Safety considerations emphasize correct sharps disposal and adherence to institutional protocols to minimize contamination and exposure risks. Vacutainers are widely used in clinical laboratories, hospitals, and blood banks for routine blood testing.