An improved radioimmunoassay for human ovarian tumor antigen NB/70K.

An improved assay for the measurement of human ovarian tumor antigen NB/70K (triton NB/70K assay) has been developed. This assay makes the accurate and reproducible estimation of serum NB/70K possible. Freezing and thawing of serum up to three times or refrigeration of diluted serum up to 7 days does not significantly alter the NB/70K levels detected by the triton NB/70K assay. NB/70K levels in different volumes of the same sample showed a linear relationship to volume, with a correlation coefficient usually above 0.98.