Which divisor is used in the plasma volume calculation when using a mass-based approach?

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Which divisor is used in the plasma volume calculation when using a mass-based approach?

In a mass-based plasma volume calculation, you estimate volume by dividing the known mass of tracer you introduced by the tracer’s concentration in plasma. The idea is that PV = amount of tracer injected (mass) ÷ plasma concentration of that tracer. The number you divide by must match the tracer’s plasma concentration used in this method. Here, the method uses a concentration of 0.025 (for example, 0.025 g per mL, or 25 mg/mL). So you divide the injected mass by 0.025 to get the plasma volume (in mL, with the appropriate unit conversions as needed). Using a different divisor would reflect a different assumed tracer concentration and would not yield the correct volume for this mass-based approach.

In a mass-based plasma volume calculation, you estimate volume by dividing the known mass of tracer you introduced by the tracer’s concentration in plasma. The idea is that PV = amount of tracer injected (mass) ÷ plasma concentration of that tracer. The number you divide by must match the tracer’s plasma concentration used in this method. Here, the method uses a concentration of 0.025 (for example, 0.025 g per mL, or 25 mg/mL). So you divide the injected mass by 0.025 to get the plasma volume (in mL, with the appropriate unit conversions as needed). Using a different divisor would reflect a different assumed tracer concentration and would not yield the correct volume for this mass-based approach.

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