A novel point-of-care test for cirrhosis based on dimeric to monomeric IgA ratio in blood: a pilot cohort study

Background and Aims: Dimeric IgA to monomeric IgA ratio (dIgA ratio) is a biomarker of gut mucosal leakage in liver cirrhosis. We evaluated the diagnostic performance of a novel point-of-care (POC) dIgA ratio test for cirrhosis. Methods: Plasma samples from people with chronic liver disease were analyzed using the BioPoint POC dIgA ratio antigen immunoassay lateral flow test. Cirrhosis was defined by Fibroscan>12.5 kPa, clinical evidence of cirrhosis or liver histopathology. POC dIgA test diagnostic accuracy was determined in a test cohort using receiver operating characteristic curve analysis; optimal cutoffs for sensitivity and specificity were then applied to a validation cohort. Results: A total of 1478 plasma samples from 866 patients with chronic liver disease were included (test cohort n = 260, validation cohort n = 606). In all, 32% had cirrhosis; 44% Child-Pugh A, 26% Child-Pugh B, and 29% Child-Pugh C. Median POC dIgA ratio was higher in cirrhosis (0.9) compared with no cirrhosis (0.4, p < 0.001), and in Child-Pugh class B/C compared with A cirrhosis (1.4 Child-Pugh B/C vs. 0.6 Child-Pugh A, p < 0.001). POC dIgA ratio test had good diagnostic accuracy for liver cirrhosis in the test cohort (area under the receiver operating characteristic curve=0.80); a dIgA ratio cutoff of 0.6 had a sensitivity of 74% and specificity of 86%. POC dIgA test accuracy was moderate in the validation cohort (area under the receiver operating characteristic curve=0.75; positive predictive value 64%, negative predictive value 83%). Using a dual cutoff approach, 79% of cirrhosis cases were correctly diagnosed and further testing was avoided in 57%. Conclusions: POC dIgA ratio test had moderate accuracy for cirrhosis. Further studies evaluating the accuracy of POC dIgA ratio testing for cirrhosis screening are warranted.