Radioimmunoassay of pregnanediol concentrations in early morning urine specimens for assessment of luteal function in women.

A radioimmunoassay has been developed that employs a readily available radioligand 3H-20alpha-hydroxy-4-pregnen-3-one for the determination of pregnanediol glucuronide in urine. The unextracted steroid is assayed directly after dilution of urine with the use of an antiserum produced to a thyroglobulin conjugate of pregnanediol glucuronide. The assay has been validated, and the ability to assess luteal function by measurement of the concentration of pregnanediol glucuronide in early morning urine specimens has been demonstrated.