Description
Introduction
- The DRG:HYBRiD-XL AFP is an enzyme immunoassay for the quantitative in vitro diagnostic measurement of Alpha-fetoprotein (AFP) in serum or plasma (EDTA-, heparin- or citrate plasma).
- Only for use with the DRG:HYBRiD-XL Analyzer.
Summary and Explanation
- Alpha-fetoprotein (AFP) is a glycoprotein with a molecular weight of approximately 70 KD (1). AFP is normally produced during fetal and neonatal development by the liver, yolk sac, and in small concentrations by the gastrointestinal tract (2). After birth, serum AFP concentrations decrease rapidly, and by the second year of life and thereafter only trace amounts are normally detected in serum (3).
- Elevation of serum AFP to abnormally high values occurs in several malignant diseases (4-7), most notably nonseminomatous testicular cancer (8,9) and primary hepatocelluar carcinoma (HCC) (10). For diagnosing hepatocellular carcinoma, a combination of GP73 and AFP exhibited significantly higher diagnostic accuracy than did GP73 or AFP alone (11). In the case of nonseminomatous testicular cancer, a direct relationship has been observed between the incidence of elevated AFP levels and the stage of disease (12-13). Elevated AFP levels have also been observed in patients diagnosed with seminoma with nonseminomatous elements, but not in patients with pure seminoma (6, 12, 14-15).
- In addition, elevated serum AFP concentrations have been measured in patients with other noncancerous diseases, including ataxia telangiectasia (16), hereditary tyrosinemia (17), neonatal hyperbilirubinemia, neural tube defects (18), acute viral hepatitis (19,20), chronic active hepatitis and cirrhosis (21). Elevated serum AFP concentrations are also observed in pregnant women (22-24). Therefore, AFP measurements are not recommended for use as a screening procedure to detect the presence of cancer in the general population.
Principle of the Test
- The DRG:HYBRiD-XL AFP Kit is a solid phase enzyme-linked immunosorbent assay (ELISA) based on the sandwich principle.
- The antibody coated wells (ACW) of the reagent cartridges are coated with a monoclonal (mouse) antibody directed towards a unique antigenic site of the AFP molecule. An aliquot of patient sample containing endogenous AFP is incubated in the coated well with enzyme conjugate, which is an anti-AFP mouse monoclonal antibody conjugated with horseradish peroxidase. After incubation the unbound conjugate is washed off.
- The amount of bound peroxidase conjugate is proportional to the concentration of AFP in the sample.
- Having added the substrate solution, the intensity of color developed is proportional to the concentration of AFP in the patient sample.
