STUDIES ON HYPOALBUMINEMIA PRODUCED BY PROTEIN- DEFICIENT DIETS I. ttXr~OALBU~rE~IA AS A QUANTITATIVE MEASURE OY TISSUE PROTEIn

The realization within recent years of the prevalence and seriousness of protein deficiency has emphasized the need for some simple means of recognizing the presenc e and degree of such a condition. The only proteins capable of direct clinical measurement are those in the blood. Yet there has, so far, been no evidence that a lowered plasma protein concentration reflects accurately anything but a deficiency in the blood alone. During the course of other experiments, evidence was adduced indicating the existence of a constant relationship between losses in the total circulating plasma albumin and in the body protein as a whole. This, of course, immediately suggested a means of recognizing and evaluating total body protein deficiency. Of the plasma proteins it is only the albumin fraction which consistently decreases during an inadequate protein intake (1-3); for this reason consideration may be confined to this fraction alone. The total circulating serum 1 albumin can be readily obtained by multiplying the albumin value by the plasma volume which may be estimated from the body weight or determined directly. By subtracting this total circulating serum albumin from the normal, the number of grams of albumin by which the serum is depleted is obtained. The depletion in the tissue protein is, of course, readily measured by determining the total nitrogen loss in the urine and feces. Now if the relationship between total serum albumin depletion and total tissue Total serum albumin depletion protein depletion is represented by the equation Total protein depletion = K, the value of K is readily calculated. On the other hand if K is known and the serum albumin measured the only unknown would be the tissue protein depletion for which the equation could then be solved.