Basic Fetoprotein in Normal and Pathologic Urine

Abstract

We developed a latex agglutination nephelometric immunoassay for urinary basic fetoprotein (BFP) that functioned well and had good specificity, precision, and recovery. Reference intervals started below 0.5 μg/L, the lower limit of the range of sensitivity of the assay, and went up to 7.0 μg/L at the 97.5th percentile without age- or sex-related variation, in accordance with the NCCLS guidelines. BFP was unstable at pH 5.0 at 4° and 25°. The western blot method showed BFP found in the semen to be structurally identical to purified BFP from hepatoma ascites, in which concentration ranged from 94.2 to 145.2 μg/L and, further, to have the same molecular weight and reactivity with a monoclonal antibody. BFP levels were elevated in cases urinary BFP concentration included ureter stone, infection, and prostate and bladder cancer. Moreover, BFP concentration correlated closely with that of α2-macroglobulin, indicating that BFP is probably secreted locally in close pathophysiologic association with post-renal hemorrhage. We thus conclude that BFP is a urinary nonspecific marker for inflammation or tumor. The best indication for BFP as a tumor marker may be follow-up when diagnosis of genitourinary cancer is definite.