Detection and quantification of protein-losing enteropathy with indium-111 transferrin

Localisation and quantification of protein loss in protein-losing enteropathy (PLE) is useful in the clinical management of hypoalbuminaemia. Indium-111 transferrin offers the opportunity of combining localisation and quantification using a single agent. Twenty-five studies were performed in 23 patients with suspected PLE: 111In-transferrin was prepared by incubating autologous cell-free plasma with 111In chloride in vitro for 15 min. Protein loss was quantified by comparing whole-body counts recorded with an uncollimated gamma camera at 3 h and 5 or 6 days after injection of 111In-transferrin. Gamma camera imaging performed at 3 and 24 h after injection demonstrated a site of protein loss in 15 studies. Whole-body 111In 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 111In excretion was normal in nine and elevated at 22% in a further patient with carcinoid syndrome. Overall, the mean whole-body 111In excretion in studies 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 was 7.5% (SD 6.7%) (n=10). This technique should be useful for the combined approach of localising and quantifying protein loss in PLE.