Basic Principle of Blood Volume Analysis
The BVA-100 Blood Volume Analyzer quantifies circulating blood volume utilizing the gold standard methodology, the indicator tracer dilution technique. A dose of Volumex® Albumin I-131 tracer is injected intravascularly. Once the tracer has fully circulated in the bloodstream, a series of small blood samples are drawn. The BVA-100 automatically calculates patient blood volume by comparing the concentration of undiluted tracer prior to injection to the tracer concentration diluted in the patient blood samples.
The human figures represent sequential calculated blood volumes at the recommended intervals for drawing blood samples after tracer injection.
As the Volumex® tracer transudates from the intravascular to the extravascular space (depicted as the pink dots moving outside the red vein), the quantity of tracer decreases intravascularly implying a higher dilution factor and therefore higher blood volume.
The red line represents is the regression calculation of the analyzed draws to time zero or time of injection, which indicates the level of true total intravascular blood volume.
The red line is also a measure of albumin transudation, a measure of capillary permeability.
The blue line represents the declining radioisotope count intravascularly over the duration of the test.