Detection of alpha-fetoprotein and hepatitis-B surface antigen in blood spotted on filter paper: use as a screen for hepatocellular carcinoma in Alaska Natives

Abstract

A program of twice yearly testing of Alaska Native carriers of hepatitis-B surface antigen (HBsAg), for alpha-fetoprotein elevations as an indicator of early hepatocellular carcinoma has been established in Alaska. Because many HBsAg carriers live in remote regions of Alaska, logistical and cost considerations complicate the efficiency of this program. We evaluated the feasibility of using blood spotted onto mail-in cards as a system of blood collection and commercial assays for alpha-fetoprotein and HBsAg testing. We compared alpha-fetoprotein levels and the detection of HBsAg in both plasma and blood spots from HBsAg-positive carriers, normal volunteers, and pregnant females. There was good correlation between serum and blood spot AFP levels (r = 0.94, p < 0.001) over a wide range of serum alpha-fetoprotein levels. alpha-fetoprotein and HBsAg remained detectable in blood spots stored at room temperature for more than 8 weeks. The sensitivity of detection of HBsAg in blood spots was not as great in blood spots when compared to plasma levels. This system has been incorporated into the hepatocellular carcinoma screening program in Alaska. It should also prove feasible and economical for such screening to be undertaken in developed countries and possibly make alpha-fetoprotein screening affordable in those developing countries where the prevalence of hepatitis-B virus infection is high.