Ms Carla Scuderi1, Dr Suzanne Parker3, Mrs Margaret Jacks1, Dr George John1, Dr Brett McWhinney4, Dr Jacobus Ungerer4, Prof Andrew Mallett7,8,10,11, A/Prof Helen Healy1,7, Prof Jason Roberts3,5,6,9, A/Prof Christine Staatz2
1MNHHS Royal Brisbane and Women’s Hospital, Herston, Australia, 2University of Queensland School of Pharmacy, Woolloongabba, Australia, 3Univeristy of Queensland Centre for Clinical Research, Faculty of Medicine, Brisbane, Australia, 4Pathology Queensland, Herston, Australia, 5Department of Intensive Care Medicine, RBWH, Herston, Australia, 6Division of Anaesthesiology Critical Care Emergency and Pain Medicine, Montpellier, France, 7University of Queensland Faculty of Medicine, Herston, Australia, 8Univserity of Queensland Institute of Molecular Bioscience, St Lucia, Australia, 9Department of Pharmacy, RBWH, Herston, Australia, 10Department of Renal Medicine Townsville Univsersity Hospital, Douglas, Australia, 11College of Medicine and Dentistry, James Cook University, Douglas, Australia
Background
Kidney transplant patients undergo repeated and frequent venepunctures in the management of their allograft. Microsampling methods that use a finger-prick draw of capillary blood, such as dried blood spot (DBS) and volumetric absorptive microsamplers (VAMS), have the potential to dramatically reduce the burden of and the volume of blood loss with venepuncture.
Methods
This study aimed to examine the predictive performance of microsampling for simultaneous measurement of tacrolimus, mycophenolic acid and prednisolone concentrations compared to gold standard venepuncture in adult kidney transplant patients. Blood samples for immunosuppressant drug measurement were simultaneously collected using DBS and VAMS and venepuncture in 40 adult kidney transplant recipients, immediately prior and 2-hours after immunosuppressant dosing. Drug concentrations were measured via high-performance liquid chromatography. Samples taken via the three collection methods were compared using Passing-Bablok regression and bias was assessed using Bland-Altman analysis. Drug concentrations measured via microsampling and venepuncture were also compared through estimation of the median prediction error (MPE) and median absolute percentage prediction error (MAPE).
Results
There was a systematic difference between tacrolimus DBS and venepuncture with a Passing-Bablok regression slope of 1.06 (1.01-1.13) and between tacrolimus VAMS and venepuncture with a slope of 1.08 (1.03-1.13). Tacrolimus values were adjusted for this difference, with corrected values confirming elimination of systematic difference. No systematic difference was observed when comparing DBS or VAMS with venepuncture for mycophenolic acid and prednisolone. Tacrolimus (corrected), mycophenolic acid and prednisolone microsampling values when compared to corresponding venepuncture values met MPE and MAPE predefined acceptability limits of <15%
Discussion
The ability to measure multiple immunosuppressant concentrations from a microsample collected in a controlled environment is an exciting development in kidney transplant patient care.
Biography:
Carla Scuderi BPharm M Clin Pharm Phd (candidate)
Carla Scuderi a pharmacist with over 20 year’s experience is the Pharmacist Kidney Health Team Leader based at Royal Brisbane and Women’s hospital. Carla is currently the co-chair of the Society of Hospital Pharmacists Nephrology special interest group and is a member of the CARI guidelines steering committee and Kidney Health Australia clinical advisory committee.
Her previous roles include being a community pharmacy manager and owner, a Quality Use of Medicine facilitator for the National Prescribing Service. Carla is currently undertaking a PhD investigating microsampling and the pharmacist’s role in kidney transplants.