Therapeutic drug monitoring of tacrolimus by liquid chromatography–tandem mass spectrometry: Is it truly a routine test?

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Analytical technologies in the biomedical and life sciences, 2012-02, Vol.883-884, p.108-112
• Main Authors: Taylor, Paul J., Franklin, Michael E., Tai, Chun-Hui, Pillans, Peter I.
• Format: Article
• Language: English
• Subjects: Calibration; Chromatography; Chromatography, High Pressure Liquid - methods; Drug Monitoring - methods; Drug Monitoring - standards; Drugs; HPLC; Humans; Immunosuppressive Agents - blood; Linear Models; Liquids; Mass spectrometry; Monitoring; Phospholipids - blood; Reproducibility of Results; Routines; Tacrolimus; Tacrolimus - blood; Tandem mass spectrometry; Tandem Mass Spectrometry - methods; Therapeutic drug monitoring; Transplantation; Zinc
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2011.06.024

Therapeutic drug monitoring of tacrolimus by high-performance liquid chromatography–tandem mass spectrometry has become standard practice. We report on the long-term (4.5 years) use of one such method. Whole blood samples (25μL) were treated with zinc sulphate (100μL) and acetonitrile containing ascomycin (internal standard, 250μL). A high-performance liquid chromatography–tandem mass spectrometer operating in positive ion mode with an electrospray interface was used. Chromatography was performed on a TDM C18 cartridge column (10mm×2.1mm, 10μm, Waters) using a switch gradient. A total of 4029 batches were analyzed for tacrolimus; this comprised of 81950 analyses of which 61027 were patient samples. Calibration curves (1.0–50μg/L) were run on 1765 occasions (mean r2=0.999; range r2=0.988–0.999). Inter-batch accuracy and imprecision of the method (2.5, 12.5 and 30.0μg/L), when in routine use, was 97.6–98.5% and