DOES CREATININE ADJUSTMENT OF URINARY PREGNANEDIOL GLUCURONIDE REDUCEOR INTRODUCE MEASUREMENT ERROR

Correlation between urinary pregnanediol and serum progesterone measur ements and the influence of age, race, smoking and urinary creatinine adjustment was determined during the luteal phase of the menstrual cyc le in 175 volunteers. A decline in serum progesterone was observed wit h increasing age. Mean baseline urinary creatinine declined with incre asing age in non-smokers and was not affected by race or baseline weig ht. An excellent correlation between urinary pregnanediol glucuronide and serum progesterone levels existed except when urinary pregnanediol concentrations were adjusted using creatinine measurements in older i ndividuals. Adjustment of urinary pregnanediol glucuronide concentrati on using creatinine measurement is therefore discouraged.