Serum collected for testing should be drawn using a syringe without anticoagulant, because serum is the liquid that remains after blood has clot.

Serum collected for testing should be drawn using a syringe without anticoagulant, because serum is the liquid that remains after blood has clot.

• A. True
• B. False
• C. It depends on the test
• D. Serum is obtained from plasma

Answer: (A)

Serum is the liquid that remains after blood has clotted and the clot is removed. To obtain serum, you collect blood in a tube without anticoagulant, allow it to clot, then centrifuge to separate the clot from the liquid. If an anticoagulant were used, the blood would not clot and the separated liquid would be plasma, which contains fibrinogen and other clotting factors. So the statement is true: serum is obtained from clotted blood, hence no anticoagulant is used in collection. Some tests may use plasma instead, depending on the assay requirements, but that doesn’t change what serum is.

Serum is the liquid that remains after blood has clotted and the clot is removed. To obtain serum, you collect blood in a tube without anticoagulant, allow it to clot, then centrifuge to separate the clot from the liquid. If an anticoagulant were used, the blood would not clot and the separated liquid would be plasma, which contains fibrinogen and other clotting factors. So the statement is true: serum is obtained from clotted blood, hence no anticoagulant is used in collection. Some tests may use plasma instead, depending on the assay requirements, but that doesn’t change what serum is.