Evaluation of performance of measurement of faecal α(1)-antitrypsin clearance and technetium-99m human serum albumin scintigraphy in protein-losing enteropathy.

BACKGROUND AND AIM: Our study aimed to compare the performance of faecal α(1)-antitrypsin clearance (AATC) and radiolabelled human serum albumin (HSA) scintigraphy in protein-losing enteropathy (PLE).

METHODS: Patients studied by both AATC and technetium-99m ((99m)Tc)-labelled HSA scintigraphy were recruited and categorized into PLE and non-PLE groups based on clinical and laboratory findings. The performance of AATC and (99m)Tc-labelled HSA scintigraphy was evaluated using clinical diagnosis of PLE as a gold standard.

RESULTS: 29 patients were recruited and 13 patients were considered to have definite PLE (PLE group). In the PLE group, all patients had a positive HSA scinigraphy and 10 (77%) had demonstrable positive tracing in the early phase. Conversely, only 6 of them (46%) had elevated AATC level (>13 m/day). Results of (99m)Tc-labelled HSA scan (but not AATC) showed significant agreement with the clinical diagnosis (κ 0.35, p = 0.013). (99m)Tc-labelled HSA scintigraphy carried higher sensitivity (100 vs. 46%) and negative predictive value (100 vs. 63%) compared to AATC in diagnosing PLE. The correlation between the results of these two investigations was only modest (κ 0.27, p = 0.04). The area under the receiver operating characteristic curve of AATC level showed no optimal diagnostic cut-off for PLE.

CONCLUSION: (99m)Tc-labelled HSA scintigraphy was superior to AATC in diagnosing PLE.