Gc-globulin scavenges actin released from necrotic hepatocytes to the extracellular space. In 77 patients with fulminant hepatic failure (FHF) (excluding patients treated with liver transplantation), admission levels of serum Gc-globulin and degree of complexing with monomeric actin (complex ratio) were determined to evaluate their predictive values in relation to survival/nonsurvival. Gc-globulin levels were significantly reduced in 47 nonsurvivors, compared with 30 survivors (96 +/- 71 mg/L vs. 169 +/- 101 mg/L, P < .001), whereas the complex ratio in nonsurvivors did not differ significantly from that of survivors. Gc-globulin levels were significantly lower in 59 patients with non-acetaminophen-induced FHF, compared with 18 patients with acetaminophen-induced FHF (P < .01). Using a cutoff level of serum Gc- globulin of 100 mg/L, a lesser value correctly predicted nonsurvival in 79 percent of patients with non-acetaminophen-induced FHF, whereas a higher value predicted survival in 60 percent. In patients with acetaminophen-induced FHF, nonsurvival was correctly predicted in 100 percent of patients and survival in 53 percent. In comparison, the King's College Hospital (KCH) criteria correctly predicted nonsurvival and survival in 69 percent and 57 percent, respectively, of the same non-acetaminophen-induced FHF patients and in 60 percent and 38 percent, respectively, of the acetaminophen-induced FHF patients. Thus, in our study population, the predictive properties of Gc-globulin were in the same range as the KCH criteria. An advantage of Gc-globulin is that it gives an estimate of the outcome already on admission. Acute liver transplantation should be considered in FHF patients with Gc-globulin less than 100 mg/L.