What is the function of a centrifuge in preparing specimens?

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Multiple Choice

What is the function of a centrifuge in preparing specimens?

Explanation:
Centrifugation uses centrifugal force to separate a mixture into layers based on density. In preparing blood specimens, this allows the dense cellular elements (red and white cells, platelets) to settle at the bottom, forming a pellet, while the lighter liquid portion—plasma if a anticoagulant was used, or serum if the blood was allowed to clot—remains as the clear upper layer. This density-based separation is exactly why spinning the sample is used: it yields a clean liquid component for testing without cellular debris, which can interfere with many assays. The top liquid (plasma or serum) is what many analyses rely on, while the bottom cell layer can be discarded or used for other tests. For context, you obtain plasma when you spin a blood sample treated with an anticoagulant, and you obtain serum after allowing clotting and then centrifuging. The other options aren’t the function of a centrifuge: lysing cells is achieved by disruption of membranes or chemical means, preserving samples involves temperature and additive stability, and measuring viscosity is done with a viscometer, not a centrifuge.

Centrifugation uses centrifugal force to separate a mixture into layers based on density. In preparing blood specimens, this allows the dense cellular elements (red and white cells, platelets) to settle at the bottom, forming a pellet, while the lighter liquid portion—plasma if a anticoagulant was used, or serum if the blood was allowed to clot—remains as the clear upper layer. This density-based separation is exactly why spinning the sample is used: it yields a clean liquid component for testing without cellular debris, which can interfere with many assays. The top liquid (plasma or serum) is what many analyses rely on, while the bottom cell layer can be discarded or used for other tests. For context, you obtain plasma when you spin a blood sample treated with an anticoagulant, and you obtain serum after allowing clotting and then centrifuging. The other options aren’t the function of a centrifuge: lysing cells is achieved by disruption of membranes or chemical means, preserving samples involves temperature and additive stability, and measuring viscosity is done with a viscometer, not a centrifuge.

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