Predictive value of actin‐free Gc‐globulin in acute liver failure

Serum concentrations of the actin scavenger Gc‐globulin may provide prognostic information in acute liver failure (ALF). The fraction of Gc‐globulin not bound to actin is postulated to represent a better marker than total Gc‐globulin but has been difficult to measure. We tested a new rapid assay for actin‐free Gc‐globulin to determine its prognostic value when compared with the King's College Hospital (KCH) criteria in a large number of patients with ALF. A total of 252 patients with varying etiologies from the U.S. ALF Study Group registry were included; the first 178 patients constituted the learning set, and the last 74 patients served as the validation set. Actin‐free Gc‐globulin was determined with a commercial enzyme‐linked immunosorbent assay kit. The median (range) actin‐free Gc‐globulin level at admission for the learning set was significantly reduced compared with controls (47 [0‐183] mg/L vs. 204 [101‐365] mg/L, respectively, P < 0.001). Gc‐globulin levels were significantly higher in spontaneous survivors than in patients who died or were transplanted (53 [0‐129] mg/L vs. 37 [0‐183] mg/L, P = 0.002). A receiver operating characteristic curve analysis showed that a 40 mg/L cutoff level carried the best prognostic information, yielding positive and negative predictive values of 68% and 67%, respectively, in the validation set. The corresponding figures for the KCH criteria were 72% and 64%. A new enzyme‐linked immunosorbent assay for actin‐free Gc‐globulin provides the same (but not optimal) prognostic information as KCH criteria in a single measurement at admission. Liver Transpl 13:1324–1329, 2007. © 2007 AASLD.