Vacuum Blood Collection Glass Tubes

An evacuated blood collection tube is a small piece of precision engineering. It is sealed under a calibrated vacuum so that, when the rubber stopper is pierced by the collection needle, exactly the right volume of blood is pulled in automatically — no syringe, no guesswork. The pre-set vacuum and the additive in the tube are matched to draw the correct ratio for the test.

The tubes are color-coded by their additive — EDTA for hematology, citrate for coagulation, clot activator or gel for serum chemistry, and so on — a universal code that tells the phlebotomist and lab exactly what each tube is for.

Venous blood collection across hematology (EDTA), coagulation (citrate), clinical chemistry (serum/gel), and cross-match and blood-bank work, in diagnostic laboratories, hospital and clinic phlebotomy, and research sample collection.

A glass tube in Type I borosilicate or Type II soda-lime with a penetrable rubber stopper or safety closure, sealed under a calibrated vacuum and pre-filled with the appropriate additive (EDTA, citrate, heparin, clot activator, separator gel). The cap color identifies the additive, and the draw volume is set by the vacuum.

The vacuum and additive ratio are calibrated, so tubes are filled to the indicated draw and gently inverted the specified number of times to mix the additive without hemolysis; under- or over-filling can invalidate certain tests. The order of draw and the color code are followed strictly in phlebotomy. Tubes are sterile and dated, and the vacuum must be intact at use.

The glass tube is tubing-converted, the additive is dosed in, and the tube is stoppered and evacuated to a precise vacuum, then sterilized and dated. Vacuum accuracy (for correct draw volume), additive dosing and sterility are the critical controls; the cap is color-coded to the additive and the system is QC-tested for draw performance.