A simple immunoradiometric assay for human follicle stimulating hormone (hFSH) was developed using a pair of monoclonal antibodies
obtained from commercial sources. The system developed makes use of a capture antibody covalently coupled to magnetisable
cellulose, which is a more economical and stable immunosorbent as compared to the other solid phases. The detector antibody
is labeled with125I using the chloramine-T oxidation method and purified by gel filtration. After initial cross-matching of the capture and
detector antibodies, various assay parameters have been optimised. This assay does not show any significant cross reactivity
with homologous hormones. A number of serum samples from men and women from reproductive age group was screened and compared
with another commercially available kit (r=0.98). Sensitivity of the assay is 1.4 mIU/ml, interassay variation is <5% and intraassay variation around 15%. The assay
is reproducible and sensitive enough for regular estimation of serum hFSH and is relatively inexpensive.