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 stopper is pierced by the collection needle, the right volume of blood is drawn in automatically. The vacuum and the additive inside are matched to give the correct blood-to-additive ratio for the test.

Tubes are color-coded by additive: EDTA for hematology, citrate for coagulation, clot activator or gel for serum chemistry, a convention that tells the phlebotomist and the lab exactly what each tube is for.

Glass collection tubes serve venous blood collection for hematology, coagulation, clinical chemistry and blood-bank work in hospitals, clinics and diagnostic laboratories, as well as research sample collection. Glass remains the preferred material for some tests, including certain coagulation and trace-element assays, and for labs that freeze, centrifuge at high speed or store samples long term. Device makers and kit assemblers buy the glass tubes to fill, stopper and evacuate under their own registrations.

The tube is a straight-sided cylinder with a rounded closed base and an open, fire-polished rim, made in the standard 13 mm and 16 mm diameters in several lengths. Type I borosilicate gives the highest chemical resistance and thermal shock tolerance; Type II soda-lime suits many routine applications. A complete tube adds a penetrable rubber stopper or safety cap, the additive and the calibrated vacuum that sets the draw volume.

In a complete tube, the vacuum and additive are calibrated together, so tubes are filled to the indicated draw and gently inverted to mix without hemolysis; under-filling can invalidate some tests. Phlebotomists follow a fixed order of draw by cap color. The finished tube is a regulated in-vitro diagnostic device, so ask us for the regulatory documentation that applies to the specific tube and market you have in mind.

We convert the tubes from borosilicate or soda-lime glass tubing to controlled length, diameter and wall thickness, fire-polish the rim and inspect each lot for dimensions and defects. Certificates of analysis and compliance documentation are available on request. Plain tubes ship in racks or bulk packs for your own assembly line; complete evacuated tubes with stoppers, additives and labels can be supplied to your specification. Send us your diameter, length and draw volume for a quote.