Triamcinolone acetonide (TA) is classified as an S9 glucocorticoid in the 2014 Prohibited List published by the World Anti-Doping Agency, which caused it to be prohibited in-competition when administered orally, intravenously, intramuscularly or rectally. The Minimum Required Performance Level (MRPL) for the detection and identification of glucocorticoids is 30 ng/mL. Other common local injection routes, such as intraarticular, intratendinous, or intrabursal injection, are not prohibited. The purpose of this study was to analyze the TA and triamcinolone (T) concentrations in urine after a single injection of TA in patients to determine if it would produce a positive result. This study was performed on 40 patients with sports injuries or joint pains. TA was administered locally (doses varied from 12 to 80 mg). Samples were extracted using a solid-phase extraction column, followed by hydrolysis and liquid extraction using diethyl ether. The elution solvents were collected and dried. The dried residue was reconstituted and assayed by performing liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive ionization mode using electrospray ionization and multiple-reaction monitoring as the acquisition mode. The results demonstrated that the concentrations of both TA and T in urine exceeded the MRPL (30 ng/mL) after a single local injection. We obtained positive results for TA in 25 patients, and a positive result for T in one patient. Furthermore, the metabolic situation of TA, a long-acting glucocorticoid, was not an exact linear model. The highest concentrations of TA and T appeared 1-4 h after injection. This information could be useful for limiting the misuse of TA by athletes. We suggest that athletes be aware when using TA injections during a competition period and obtain approval for therapeutic use exemption prior to using TA. (C) 2014 The Authors. Published by Elsevier Ireland Ltd.