The APRI may be enhanced by the use of the FIBROSpect II in the estimation of fibrosis in chronic hepatitis C

Background: Multiple serum markers to estimate hepatic fibrosis in chronic liver disease have been proposed. The AST/Platelet Ratio Index (APRI) is a simple biochemical index that has been shown to be useful and accurate in about 50% of patients with chronic hepatitis C. We determined if the combination of the APRI and the FIBROSpect II, a commercially available hepatic fibrosis marker that measures 3 components of the extracellular hepatic matrix, would further help distinguish mild from significant fibrosis in a group of patients with chronic hepatitis C. Methods: In an outpatient setting, 93 consecutive patients were studied who were undergoing staging liver biopsy for chronic hepatitis C who had a liver biopsy length ≥ 1.5 cm. All had blood drawn at the time of the biopsy. Liver biopsies were staged for fibrosis by the Batts Ludwig criteria (F0-F4). Patients with previous anti-viral therapy, hepatocellular carcinoma, an organ transplant, or co-infection with HIV or hepatitis B were excluded. The APRI was calculated and FIBROSpect II determined. Results: The AUC of the ROC curve for the APRI and FIBROSpect II were 0.887 and 0.879 respectively. Using cutoffs of ≤ 0.42 for mild fibrosis (F0-F1) and ≥ 1.2 for significant fibrosis, the APRI correctly estimated 19 of 20 patients with mild fibrosis for an NPV of 95.0%, and 31 of 33 patients with significant fibrosis for a PPV of 93.6%. The FIBROSpect II also works best utilizing 2 cutoffs, and using cutoffs of ≤ 25 and ≥ 85 it correctly identified 18 of 18 patients with mild fibrosis and all 26 patients with significant fibrosis for an NPV and PPV of 100% for both. Among the 40 patients who could not be classified by the APRI, an additional 16 could be correctly classified using the FIBROSpect II with cutoffs of ≤ 25 and ≥ 85. This lowered the indeterminate zone from 43.0 to 25.8%. By combining the APRI and the FIBROSpect II, the AUC for the ROC curve improved significantly to 0.931 (p = 0.013). Conclusions: The APRI and the FIBROSpect II are both accurate tests for separating mild from significant fibrosis. By using the APRI as the initial screen, > 50% of patients with mild or significant fibrosis can be correctly identified. If the patient falls in the indeterminate zone, then the more expensive FIBROSpect II could be obtained. This strategy could decrease the number of liver biopsies.