Basic fetoprotein in normal and pathologic urine

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 microgram/L, the lower limit of the range of sensitivity of the assay, and went up to 7.0 micrograms/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 degrees C and 25 degrees C. 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 micrograms/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 alpha 2-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.