Evaluation of Performance of Measurement of Faecal α1-Antitrypsin Clearance and Technetium-99m Human Serum Albumin Scintigraphy in Protein-Losing Enteropathy

Abstract

Background and Aim: Our study aimed to compare the performance of faecal α₁-antitrypsin clearance (AATC) and radiolabelled human serum albumin (HSA) scintigraphy in protein-losing enteropathy (PLE). Methods: Patients studied by both AATC and technetium-99m (^99mTc)-labelled HSA scintigraphy were recruited and categorized into PLE and non-PLE groups based on clinical and laboratory findings. The performance of AATC and ^99mTc-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 ^99mTc-labelled HSA scan (but not AATC) showed significant agreement with the clinical diagnosis (ĸ 0.35, p = 0.013). ^99mTc-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 (ĸ 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:^99mTc-labelled HSA scintigraphy was superior to AATC in diagnosing PLE.

The clinical characteristics of lupus related protein-losing enteropathy in Hong Kong Chinese population: 10 years of experience from a regional hospital

“…[22][23][24] Chau et al found that positive images in the early phase of the scan are more useful in identifying the primary site of protein loss and detecting multifocal involvement. 21 Our observation does not support this finding because most of our patients showed diffuse inflammatory change in the GI tract and the early positive image may represent intermittent protein leakage at this instant only.…”

“…99m Tc-labeled HSA had very high sensitivity (95.8%) in the detection of protein leakage in our study, comparable to the previous studies. 20,21 Chau et al found superior performance of the 99mTc-labelled HSA scintigraphy over fecal AATC with higher sensitivity. 21 However, there are several pitfalls of 99m Tc-labeled HSA scintigraphy for PLE.…”

Protein-losing enteropathy associated with or without systemic autoimmune disease

“…The detection rate of protein leakage in PLE was very good (97.3%) in our study, compared with previous studies [30,31]. Chau and colleagues found 99m Tc-labeled HSA scintigraphy to be superior to fecal AATC, with higher sensitivity.…”

Protein-Losing Enteropathy in Systemic Lupus Erythematosus: 12 Years Experience from a Chinese Academic Center

“…99 m Tc-HSA scintigraphy is regarded as the diagnostic tool of choice for patients with PLE [2] , [3] , [35] , as it has very high sensitivity for diagnosis and localization of PLE [36] – [38] . However, its application is limited because many hospitals are not able to perform the procedure.…”