Use of 51-CrCl-3 in the diagnosis of protein-losing enteropathy.

A number of isotopically labelled compounds, including 1311 albumin, 13II polyvinylpyrrolidone (131I PVP), in vitro labelled 51Cr albumin, and in vivo labelled plasma proteins with 51Cr Cl3, have been used to detect protein loss into the gastrointestinal tract. 1311 albumin (Veall and Vetter, 1958) is most suitable for determining albumin turnover rate, but is of little value in the assessment of enteric loss. 1311 PVP (Gordon, 1958, 1959), a synthetic polymer with a short half life (Rubini and Sheehy, 1961), is not suitable for estimating albumin degradation and its value in enteric protein loss is purely qualitative. In vitro 51Cr albumin (Waldmann, 1961, 1964) has the advantage of being a natural compound, the chromium released after digestion is not reabsorbed, and the stool activity is a measure of enteric protein loss. However, the short half life makes this method unsuitable for albumin turnover studies. The labelling of plasma proteins in vivo would theoretically be the most physiological means of assessing enteric protein loss and possibly albumin turnover. However, only two studies using this method (Rubini and Sheehy, 1961; Guillen and Peterson, 1964) have so far been published. The present report evaluates the use of 31Cr C13 in vivo as a method for determining enteric loss and daily turnover of plasma proteins. Thirty-one patients were given 51Cr C13 intravenously, and the distribution of the isotope in the blood, the daily loss in the urine and faeces, and the half life of the isotope were measured. Our studies show that the intravenous injection