What centrifugation speed range and time are standard for separating serum?

• A. 1000-2000 g for 10 minutes
• B. 1500-2500 g for 5 minutes
• C. 3000-4000 g for 20 minutes
• D. 500-1000 g for 30 minutes

Answer: (A)

Separating serum relies on spinning the clotted blood so that the dense cells sediment to the bottom while the clear liquid serum remains on top. The standard practice uses a moderate centrifugal force for a short, practical time: about 1000–2000 g for roughly 10 minutes. This range is enough to achieve a clean separation quickly without applying excessive mechanical stress to the cells. Spinning at higher forces (for example, 3000–4000 g for 20 minutes) increases the risk of damaging cells and causing hemolysis or other artifacts that can contaminate the serum and affect test results. Conversely, spinning too slowly or too long at low forces (such as 500–1000 g for 30 minutes) may not fully separate the serum from cells, leading to residual cells or clot remnants in the sample. Therefore, the combination of 1000–2000 g for about 10 minutes represents the conventional balance for reliable serum separation.