Urine ratio of tetrahydrocortisol to tetrahydrodeoxycortisol to screen for the systemic administration of cortisone and hydrocortisone

We use gas chromatography-mass spectrometry (GC-MS) to determine the urine peak area ratio of tetrahydrocortisol (THF) to tetrahydrodeoxycortisol (THS) in spot urine samples of eight male volunteers after a single intramuscular injection of 100 mg hydrocortisone (HC) and after a single oral administration of 10 mg HC at six different post-treatment times over 24 h with 1 week between the two treatments. Control spot urine samples were also obtained from a group of 100 volunteers of each sex for GC-MS analysis. In addition, one female volunteer was collected for GC-MS and isotope ratio mass spectrometry (IRMS) analysis after a single oral administration of 40 mg HC and 40 mg cortisone (C) at 15 and 10 different post-treatment times over 30 h, respectively. IRMS analysis focused on the acetylated derivative of 11-keto-etiocholanolone (11KE) and 11β-hydroxy-etiocholanolone (11OHE) as target metabolites, and on androsterone (A) as an endogenous reference compound (ERC) for calculating the corresponding δ13C (‰) depletion values. There was a small but significant sex-related difference for the THF/THS ratio in the control group with mean THF/THS ratio values of 10 and 13.5 for women and men, respectively. A cut-off value of 28 (mean + 2 S.D.) for the THF/THS ratio offered a narrow detection window with 39% of suspicious samples after HC-oral treatment, and a wide detection window with 94% of suspicious samples after HC-intramuscular administration in men. For the woman the same cut-off value offered a wide detection window after HC and C administration with 100% and 90% of suspicious samples, respectively. On the basis of a cut-off value of 3‰ for the δ13C (‰) depletion, the exogenous origin was widely evidenced for at least one target compound in 93% and 80% of the HC and C samples, respectively. We conclude by discussing the predictive ability of the urine THF/THS ratio and its usefulness in pointing out suspicious samples resulting from the systemic administration of HC and C.