A 5-ml sample of a standard diluted 1:10,000 produces 27,200 counts in the well counter.A 5-ml sample of patient plasma, counted for the same time as the diluted standard sample, produces 99,100 counts.What is the plasma volume?

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Quizplus · Accepted Answer

The dilution principle can also be used to measure an unknown volume.Using the dilution principle, it is possible to estimate a patient's plasma volume, C₁V₁ = C₂V₂.Because the standard may be too concentrated, a portion of the standard is diluted and counted while the full-strength undiluted standard can be injected into the patient.The standard can be diluted by adding 1 ml of it to a flask, which is then filled to 500 ml with distilled water.It could then be expressed as a 1:500 diluted standard.The standard counts have to be multiplied by the dilution factor of 500 to obtain the true standard concentration that was injected into the patient.Taking this into consideration, the new equation to be used to calculate the plasma volume would be C₁V₁ = (DF)C₂V_2.

A 5-Ml Sample of a Standard Diluted 1:10,000 Produces 27,200