Creatinine (PCS1, PMBC, PCS3)
The amount of creatinine (Crn) excreted daily by an individual is relatively constant. Adjustment for Crn concentration, then, “corrects” observed analyte concentrations by accounting for daily variability in urine volume. Though not measured as an outcome in and of itself, Crn was assessed to correct the analytes studied in PCS1, PMBC, and PCS3: cortisol (PCS1), catecholamines (PCS1, PMBC), and F2-isoprostanes (PCS3). Creatinine was measured in all three studies using standard methods.
Reference
Baum, A., & Grunberg, N. (1995). Measurement of stress hormones (pp. 175-192). In S. Cohen, R. C. Kessler, & G. L. Underwood (Eds.). . New York: Oxford.