Prognostic Value of the 13 C-Methacetin Breath Test in Adults with Acute Liver Failure and Non-Acetaminophen Acute Liver Injury.

The 13 C-Methacetin breath test (MBT) is a non-invasive, quantitative hepatic metabolic function test. The aim of this prospective, multicenter study was to determine the utility of initial and serial 13 C- MBT in predicting 21 day outcomes in adults with acute liver failure (ALF) and non-acetaminophen acute liver injury (ALI). METHODS The 13 C-MBT Breath ID device (Exalenz Biosciences, Ltd.) provided the percent dose recovery (PDR) throughout 60 minutes after administration of 13 C methacetin solution as the change in exhaled 13 CO2 / 12 CO2 compared to pre-ingestion ratio on study days 1, 2, 3, 5, and 7. Results were correlated with 21-day transplant-free survival and other prognostic indices. RESULTS 280 subjects were screened for enrollment between May 2016 and August 2019. Median age of the 62 enrolled patients with adequate data was 43 years, 79% were Caucasian and 76% had ALF with the remaining 24% having ALI. The mean PDR peak on Day 1 or 2 was significantly lower in non-survivors compared to transplant-free survivors (2.3 %/hr vs 9.1 %/hr, p < 0.0001). In addition, serial PDR peaks were consistently lower in non-survivors vs survivors (p < 0.0001). The AUROC of the 13 C-MBT in the combined cohort was 0.88 (95% CI: 0.79-0.97) and higher than that provided by King's College (AUROC= 0.70) and MELD scores (AUROC=0.83). The 13 C-MBT was well tolerated with only 2 gastrointestinal adverse events reported. CONCLUSIONS The 13 C-MBT is a promising tool to estimate the likelihood of hepatic recovery in ALF and ALI patients. Use of the PDR peak data from the 13 C-MBT point of care test may assist with medical decision making and help avoid unnecessary transplantation in critically ill ALF and ALI patients.