DETECTION AND QUANTIFICATION OF PROTEIN-LOSING ENTEROPATHY WITH IN-111 TRANSFERRIN

Localisation and quantification of protein loss in protein-losing ente ropathy (PLE) is useful in the clinical managment of hypoalbuminaemia. Indium-111 transferrin offers the opportunity of combining localisati on and quantification using a single agent. Twenty-five studies were p erformed in 23 patients with suspected PLE: In-111-transferrin was pre pared by incubating autologous cell-free plasma with In-111 chloride i n vitro for 15 min. Protein loss was quantified by comparing whole-bod y counts recorded with an uncollimated gamma camera at 3 h and 5 or 6 days after injection of In-111-transferrin. Gamma camera imaging perfo rmed at 3 and 24 h after injection demonstrated a site of protein loss in 15 studies. Whole-body In-111 excretion was abnormally elevated in 13 of these, ranging from 16% to 34% (normal <10%), was not assessed in one and was less than 10% in a patient with carcinoid syndrome. In the ten studies that were negative on imaging, whole-body In-111 excre tion was normal in nine and elevated at 22% in a further patient with carcinoid syndrome. Overall, the mean whole-body In-111 excretion in s tudies with positive imaging was 21.4% (SD 6.1%) (n=14), significantly higher (P<0.01) than in studies with negative imaging, in which it wa s 7.5% (SD 6.7%) (n=10). This technique should be useful for the combi ned approach of localising and quantifying protein loss in PLE.