SummaryBackgroundThe quantitative HepQuant SHUNT test of liver function and physiology generates a disease severity index (DSI) that correlates with risk for clinical complications, such as large oesophageal varices (LEVs). A derivative test, HepQuant DuO, generates an equivalent DSI and simplifies testing by requiring only oral administration of the test solution and two blood samples at 20 and 60 min.AimsSince the DSIs measured from DuO and SHUNT are equivalent, we compared the diagnostic performance for large oesophageal varices (LEVs) between the DSIs measured from DuO and SHUNT tests.MethodsThis study combined the data from two prospectively conducted US studies: HALT‐C and SHUNT‐V. A total of 455 subjects underwent both the SHUNT test and esophagogastroduodenoscopy (EGD).ResultsDSI scores correlated with the probability of LEVs (p < 0.001) and demonstrated a stepwise increase from healthy lean controls without liver disease to subjects with chronic liver disease and no, small or large varices. Furthermore, a cutoff of DSI ≤ 18.3 from DuO had a sensitivity of 0.98 (missing only one case) and, if applied to the endoscopy (EGD) decision, would have prevented 188 EGDs (41.3%). The AUROC for DSI from DuO did not differ from that of the reference SHUNT test method (0.82 versus 0.81, p = 0.3500).ConclusionsDSI from HepQuant DuO links liver function and physiology to the risk of LEVs across a wide spectrum of patient characteristics, disease aetiologies and liver disease severity. DuO is minimally invasive, easy to administer, quantitative and may aid the decision to avoid or perform EGD for LEVs.