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Hedricks, Cynthia A.; Schramm, Willfried; & Udry, J. Richard (1994). Effects of Creatinine Correction to Urinary LH Levels on the Timing of the LH Peak and the Distribution of Coitus within the Human Menstrual Cycle. Annals of the New York Academy of Sciences, 709, 204-206.


Precision of hormonal measurements in non-24 hour urine specimens is in question, because volume of urine excreted at any point during the 24-hour day varies in concentration, and concentration of urine affects the measurement of hormone metabolites in urine. For this reason, most investigators recommend the measurement of creatinine in each urine specimen. In individuals with normal renal function, creatinine clearance rate is relatively constant (eg., in women it is about 1.Og per 24-hour day). In a more concentrated sample of urine, creatinine level would be greater than l.0g; thus the value of creatinine serves as an index of urinary concentration. Because hormonal measurements in concentrated urine are likely to be greater than those in diluted (24-hour) urine, dividing the urinary hormone value by creatinine level is one method to “correct” for variability in measurement due to variability in urinary volume. In fact, correlations between urinary and serum hor- monal concentrations are significantly improved when the urinary concentrations are corrected by creatinine level.


Reference Type

Journal Article

Year Published


Journal Title

Annals of the New York Academy of Sciences


Hedricks, Cynthia A.
Schramm, Willfried
Udry, J. Richard