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Updated: Aug 11, 2026
08:38
Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS
Published on: November 8, 2015
Beyond Trough Levels: Tacrolimus Dose Requirements and Individualized Monitoring in Kidney Transplantation
Stefan Reuter1, Dirk R J Kuypers2
1Department of Medicine D, Division of General Internal Medicine, Nephrology and Rheumatology, University Hospital Münster, Münster, Germany.
Summary
The concentration-to-dose (C/D) ratio in kidney transplant recipients reveals tacrolimus dose requirements. A low C/D ratio indicates higher dose needs and is linked to poorer outcomes, but its clinical benefit needs further study.
Area of Science:
- Nephrology
- Pharmacology
- Transplantation Medicine
Background:
- Tacrolimus trough concentrations are crucial post-kidney transplant.
- Current monitoring doesn't reflect the required tacrolimus dose.
- The concentration-to-dose (C/D) ratio offers a solution by incorporating dose information.
Purpose of the Study:
- To evaluate the utility of the tacrolimus concentration-to-dose (C/D) ratio.
- To assess the association of C/D ratio with clinical outcomes in kidney transplant recipients.
- To explore C/D ratio's potential in risk stratification.
Main Methods:
- Analysis of large registry data including tacrolimus trough concentrations and doses.
- Calculation of the concentration-to-dose (C/D) ratio.
- Correlation of C/D ratio with kidney function, rejection, viral complications, graft failure, and mortality.
Main Results:
- Low C/D ratio identifies patients needing higher tacrolimus doses.
- Lower C/D ratios are associated with impaired kidney function, rejection, BK virus complications, graft failure, and mortality.
- A graded risk is observed as C/D decreases, with better outcomes when low C/D normalizes.
Conclusions:
- The C/D ratio is a valuable, low-cost phenotype reflecting tacrolimus dose requirements.
- C/D ratio can aid in risk stratification and identifying patients for targeted exposure assessment.
- C/D ratio is not a standalone treatment guide; interpretation requires clinical context, and outcome benefits from C/D-guided interventions are unproven.
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