A radioimmunoassay for 6-keto-prostaglandin F1 alpha.

We describe a highly specific RIA for blood and urine 6-keto-PGF1 alpha, the principal metabolite of PGI2. The method requires extraction and column chromatography prior to assay and uses a tritium trace for assay monitoring. Dextran-coated charcoal is used to separate bound from free trace. Acceptable standard curve reproducibility over six assays had a mean correlation of 0.991 with a coefficient of variation of 6.61%. Good precision and accuracy data were generated with this assay, and normal human blood levels in 80 control subjects was less than 125 pg/ml. Significant elevations of blood 6-keto-PGF1 alpha were found in a high proportion of cancer patients with various solid tumor malignancies.