For clinical purposes, none of the methods used in the estimation of protein in urine, plasma, serum, transudates or exudates are satisfactory. Kjeldahl determinations are accurate but require too much time. The various methods given in textbooks on clinical pathology are rapid, but they are also grossly inaccurate. There seems, therefore, to be justification for the description of a centrifuge method which has been used in this laboratory for some time, since it combines simplicity with a considerably greater degree of reliability than any of the clinical methods possess.
The first step in the method is to test the protein containing fluid with heat and acetic acid. If more than a "moderate cloud" is obtained, the fluid should be diluted. This is necessary because the volume of
precipitated protein should not exceed 1 c.c. after centrifuging. Since the term "moderate cloud" is vague, we give in Table 1 the concentrations