Analysis of serum α-fetoprotein-L3% and des-γ carboxyprothrombin markers in cases with misleading hepatocellular carcinoma total α-fetoprotein levels.

Serum fraction of α-fetoprotein L3 (AFP-L3%) and des-γ carboxyprothrombin (DCP) are proposed serum markers for the diagnosis of hepatocellular carcinoma (HCC). We evaluated their performance in two patient populations with total AFP levels non-diagnostic for HCC. From a cohort of 150 consecutive patients with HCC, 60 patients with total AFP <200 ng/ml were identified. Additionally, 50 patients with elevated AFP and no radiological evidence of HCC, for at least one year of follow-up, were included. AFP-L3% and DCP were measured by the Liquid Phase Binding Assay System (LiBASys). In cases where AFP-L3% was undetectable, a more sensitive method based on-chip electrokinetic reaction was applied. AFP-L3% was found to be positive in 22 (36.7%) of patients with HCC and 6 (12%) of non-HCC patients. DCP was found to be positive in 26 patients with HCC (43%) and in none of the non-HCC patients. Thirty-six out of sixty (60%) patients with HCC were positive for either AFP-L3% or DCP. With the on-chip technology, AFP-L3% was found to be positive in 10 patients with HCC and in 5 patients without HCC, who tested negative by LiBASys. The final sensitivity of combined AFP, AFP-L3% and DCP testing, in the entire cohort of patients with HCC, was 84%. The specificity of AFP-L3% and DCP in the studied population was 78.5 and 100%, respectively. The addition of AFP-L3% and DCP increased the sensitivity and specificity of total serum AFP for the diagnosis of HCC. The on chip AFP-L3% assay was more sensitive but less specific compared to LiBASys.