Radioimmunoassay of alpha-fetoprotein in human serum: clinical value in patients with liver diseases

Specificities of serum alpha-fetoprotein in HBsAg+ and HBsAg- patients in the diagnosis of hepatocellular carcinoma

Serum alpha-fetoprotein level is often elevated in patients with chronic liver disease and patients with hepatocellular carcinoma. One of the most difficult problems frequently encountered in practice is differentiating hepatocellular carcinoma from chronic liver disease. This study investigated the specificity and predictive value positive of serum alpha-fetoprotein at various levels in the diagnosis of hepatocellular carcinoma, using 54 patients with histologically proven hepatocellular carcinoma and 200 patients with chronic liver disease (40 patients with chronic active hepatitis and 160 patients with cirrhosis) as nontumor controls. Among 254 patients, 170 (66.9%) were HBsAg+. A wide range of overlap (from 0 to 6,400 ng/ml) in the distribution of serum alpha-fetoprotein levels between hepatocellular carcinoma and chronic liver disease patients was observed mainly among HBsAg+ patients. In contrast, the overlapping range of serum alpha-fetoprotein levels between HBsAg- patients with hepatocellular carcinoma and chronic liver disease was remarkably narrow (from 0 to 200 ng/ml). Therefore the specificity and predictive value positive of alpha-fetoprotein at a given level were significantly lower in HBsAg+ than in HBsAg- patients, especially when alpha-fetoprotein was between 25 and 200 ng/ml. The specificities of alpha-fetoprotein at 200 ng/ml and 400 ng/ml in HBsAg+ patients were 79.8% and 91.5%, respectively, whereas these specificities were both 100% in HBsAg- patients. The predictive values positive at 200 ng/ml and 400 ng/ml in HBsAg+ patients were 53.6% and 72.5%, respectively, in contrast to 100% at both levels in HBsAg- patients. The serum alpha-fetoprotein level, which showed a predictive value positive of 95% in HBsAg+ hepatocellular carcinoma patients, was 3,200 ng/ml, whereas that in HBsAg- hepatocellular carcinoma patients, was 200 ng/ml. We conclude that serum HBsAg status should be considered when serum alpha-fetoprotein is measured as an independent test to diagnose hepatocellular carcinoma, and suggest that regular serum alpha-fetoprotein determination may be more useful in HBsAg- patients with chronic liver disease for the early diagnosis of hepatocellular carcinoma than in HBsAg+ patients.

Strain and sex differences in serum alpha-fetoprotein levels in Mus musculus

Normal levels of circulating serum alpha-fetoprotein (AFP) in different inbred strains of mice, as determined by radioimmunoassay, are reported. These strains show different and characteristic values for the mean serum AFP concentration, suggesting genetic control of the serum level of this protein. Furthermore, within each strain a difference in serum levels of the protein is observed between sexes; males have a significantly higher serum AFP concentration.

Relationship of hepatitis B surface antigen to serum alpha-fetoprotein in nonmalignant diseases of the liver

Serum alpha-fetoprotein (AFP) levels were measured by radioimmunoassay in 89 healthy adult Chinese, 170 patients with histologically verified non-malignant liver diseases, and 14 hepatitis B surface antigen (HBsAg) carriers with normal liver histology. In 97% of the healthy adults, AFP levels were under 20 ng/ml, which is then regarded as the normal upper limit. Cases with supranormally elevated AFP levels ranged from 15-51% in chronic hepatic disorders and were 33% in acute hepatitis. None of the healthy HBsAg carriers had abnormal AFP level. HBs antigenemia was found to be related to AFP elevation in chronic active hepatitis, cirrhosis, and acute hepatitis but not in chronic persistent hepatitis and healthy HBsAg carriers. The correlation could be demonstrated only when the sensitive third generation test was employed to define seropositivity of HBsAg. Events after hepatic injury induced by hepatitis B virus, rather than the HBs antigenemia itself, are probably responsible for the association. Whether the association of HBsAg and elevated serum AFP in these nonmalignant hepatic disorders contributes to the higher risk of subsequent development of hepatocarcinoma in Taiwan is unknown and requires further long-term longitudinal study.

Identification of fetal blood stains by radioimmunoassay of alpha 1-fetoprotein

Radioimmunoassay of alpha 1-fetoprotein(AFP) for medico-legal identification of fetal blood stains using a commercial kit is described. The AFP content in fetal blood stains on filter paper ranged from 21--320 ng/9 mm2. The protein was detected in stains of adult blood and retroplacental blood in only negligible amounts. Aging of the blood stains did not influence the values up to 1 month. The method is simple and sensitive enough for application to medico-legal-practice.

Increased serum alpha-fetoprotein levels in cytomegalovirus infections

Among 54 patients with a clinically and serologically verified cytomegalovirus infection, 8 (15%) had raised alpha-fetoprotein (AFP) levels in sera taken after the onset of infection. No raised serum AFP was seen in acute or convalescent sera of 45 patients with other viral diseases, including infectious mononucleosis and acute herpes simplex virus infection. No definite correlation was found between raised AFP and raised S-ALAT values, indicating hepatic damage. The highest single AFP values were seen in two immunosuppressed patients and in a patient who received a blood transfusion. Two possible explanations for this phenomenon are advanced.

Alpha1-fetoprotein in the diagnosis of hepatoma: statistical and cost benefit aspects

A rational comparison of different serum concentrations of alpha1-fetoprotein (S-AFP) in the diagnosis of hepatoma must be made. We took data on the sensitivity and specificity of different diagnostic S-AFP concentrations from the literature and evaluated them statistically and by Bayesian analysis. In our patients (hepatoma prevalence 0.028) a sensitive diagnostic concentration (30-50 ng/ml) will misdiagnose hepatoma so often that a positive test will indicate hepatoma in only 10% of cases. A positive test at a specific diagnostic concentration (500 ng/ml) indicates hepatoma in 100% of cases and is preferable in terms of cost benefit. Although the lower concentration will diagnose a larger proportion of patients with hepatoma (74% compared with 59%) the 'costs' of excluding false positives are considerable (A$2545 per extra case with 2.5% of patients suffering significant morbidity). In western societies, where the prevalence of hepatoma is low, a higher, less sensitive but more specific diagnostic S-AFP concentration is appropriate.