Serum tube

When blood clots in a serum tube, the cells and the clotting proteins form a solid part, and the clear yellow liquid left above it is serum. The laboratory spins the tube in a centrifuge to separate the two and then measures values such as cholesterol, vitamin D, ferritin and many hormones from the serum.

In a kit for home collection the serum tube is a small tube that fits onto the collection device, such as Tasso+. If the panel needs more serum than a tube holds, the kit carries a second tube or a second device.

For a buyer the tube type matters because a value measured from the wrong tube cannot be reported. Ask a supplier which tube each value in your panel needs and who decides which tubes go into each kit.

In this glossary, EDTA tube describes the other common tube, Haemolysis explains a common reason a serum sample fails, and Präanalytik covers everything that happens to a tube before analysis.