Simultaneous Determination of the Apparent ³HOH, ⁸²Br, ¹²⁵I Human Albumin and ⁵¹Cr Red Cell Volumes in Human Subjects

Abstract

A technique for performing true simultaneous determinations of body fluid compartments by means of four radioisotopes has been described. The accuracy of the method based upon in vitro experiments showed a 2 s. d. from 4.0 to 7.2%. The daily biological variations were from 0 to 2.8% (2 s. d.). A so-called steady state was approximately obtained by ³HOH, ⁸²Br, and ⁵¹Cr. Daily variations of ¹²⁵I-albumin volume could only be determined by injections twice or three times daily. As this was not done in these experiments, the daily variations of ¹²⁵I-albumin volume could not be calculated. 27 patients without fluid disturbances have been examined and the results are given in one of the Tables.

Key Words:

• ⁸²Br
• ⁵¹Cr-tagged red blood cells
• extracellular volume
• ¹²⁵I- human albumin plasma volume
• radioisotopes
• total body water
• tritiated water