Determination of Serum Testosterone Levels with Liquid Chromatography-Isotope Dilution Tandem Mass Spectrometry and Comparision with Other Immunoassays

Background: In clinical laboratories, Determination of serum testosterone levels in routine is challenging.Reliable analysis of bioavailable testosterone is difficult.Methods: After liquid-liquid extraction, Shimadzu Prominence LC unit coupled to API 3200 mass spectrometer with atmospheric pressure chemical ionisation was used to quantify serum testosterone levels.Serum testosterone results taken from tandem mass spectrometry were compared with Roche, Beckman and Abbott commercial automated testosterone immunoassaysResults: In LC-MS/MS method, linearity for testosterone was 0.005-15.915ng/mL.Recovery was 97-108% for 0.06-16 ng/mL concentration range.Intraday and inter-day CVs were 6.3,9,7; 2,2,8.7 and 1.3,0.3 for low (0.969 ng/ mL), intermediate (4.816 ng/mL) and high (8.084ng/mL) testosterone concentrations, respectively.There was a good correlation between commercial immunoassays.In method comparision, agreement was closest with Roche and LC-MS/MS method (r=0.9670).Discussion: In contrast to commercial testosterone immunoassays, LC-MS/MS method is a reliable, simple and useful method for clinical laboratory practices.