A novel 1-minute clamping bean test (CBT₁) for screening covert hepatic encephalopathy: feasibility and diagnostic performance

Covert hepatic encephalopathy (CHE) is frequently under-recognized in clinical practice. This study evaluated a novel 1-minute Clamping Bean Test (CBT₁) for CHE screening.

In this two-center study conducted from September 2023 to September 2026, participants underwent both the Psychometric Hepatic Encephalopathy Score (PHES) and CBT₁. Cirrhotic patients were followed for 1 year.

In total, 336 healthy individuals and 130 cirrhotic patients were enrolled_. In healthy individuals, CBT₁ was independent of sex and declined with age, particularly beyond 50 years, and to a lesser extent with education. In cirrhotic patients, CBT₁ was significantly lower in those with than without CHE (21.3 ± 5.4 vs. 27.8 ± 5.4 beans, P < 0.001). With a cut-off of 24.5, CBT₁ achieved an AUC of 0.799 (95% CI: 0.724-0.873), with a sensitivity 74.0%, specificity71.7%, and accuracy 73.1%. CBT₁ correlated significantly with all five PHES subtests (all P < 0.001). In a subgroup of 8 patients, CBT₁ improved significantly after 10 days of lactulose therapy (median 14.5 to 17 beans, P = 0.008). Over 1-year follow-up, CBT₁ positivity was associated with mortality (P = 0.024) and hospital readmission (P = 0.046).

CBT₁ showed diagnostic accuracy comparable to PHES, with additional advantages of being time-saving and home-applicable. By translating a fundamental daily motor skill into a quantifiable biomarker, CBT₁ is a promising screening tool for CHE.