How is serum separated from clot and what centrifugation parameters are typical?

How is serum separated from clot and what centrifugation parameters are typical?

• A. Allow clot to form (15–30 minutes), then centrifuge at about 1,300–2,000 x g for 10–15 minutes; separate serum promptly.
• B. Spin immediately at 3,000 x g for 5 minutes and refrigerate the serum.
• C. Freeze the clot for 30 minutes, then centrifuge at 500 x g for 20 minutes.
• D. Do not centrifuge; allow serum to separate by gravity.

Answer: (A)

The main idea is that serum is obtained after the blood has fully clothed and the clot is then separated from the liquid by centrifugation at a moderate speed. Allowing the clot to form for about 15–30 minutes lets this process complete so no clot fragments remain in the serum. Following that with centrifugation at roughly 1,300–2,000 x g for 10–15 minutes gives a clean separation, producing clear serum as the supernatant while the clot and cells pellet at the bottom. Separating promptly is important to minimize metabolic changes in the sample and to reduce the chance of clot reformation or cellular activities altering analyte levels. Spinning immediately without a clot, or using too high a speed, can cause hemolysis or improper separation and doesn’t yield true serum. Not centrifuging or relying on gravity alone usually results in unreliable separation with residual clot material in the fluid. Freezing the clot or other nonstandard steps aren’t part of the typical, validated procedure.

The main idea is that serum is obtained after the blood has fully clothed and the clot is then separated from the liquid by centrifugation at a moderate speed. Allowing the clot to form for about 15–30 minutes lets this process complete so no clot fragments remain in the serum. Following that with centrifugation at roughly 1,300–2,000 x g for 10–15 minutes gives a clean separation, producing clear serum as the supernatant while the clot and cells pellet at the bottom. Separating promptly is important to minimize metabolic changes in the sample and to reduce the chance of clot reformation or cellular activities altering analyte levels.

Spinning immediately without a clot, or using too high a speed, can cause hemolysis or improper separation and doesn’t yield true serum. Not centrifuging or relying on gravity alone usually results in unreliable separation with residual clot material in the fluid. Freezing the clot or other nonstandard steps aren’t part of the typical, validated procedure.