AFP and hepatocellular carcinoma: If we restrict our analysis to only those VA patients with frequent AFP tests (no more than nine months between AFP tests) then the improvement of the PEB algorithm with AFP compared to the standard thresholding approach was 4.37% (57.28% vs 52.91%) when the screening-level false positive rate was set to 10% and all positive screens in HCC cases were considered to be true positive screens.