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Updated: Oct 31, 2025
08:38
Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS
Published on: November 8, 2015
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Retrospective Analysis of Tacrolimus Intrapatient Variability as a Measure of Medication Adherence
Jordana Herblum1, Niki Dacouris2, Michael Huang2
1Keenan Research Summer Student Program, St. Michael's Hospital, Toronto, ON, Canada.
Canadian Journal of Kidney Health and Disease
|June 30, 2021
Summary
Intrapatient variability (IPV) in tacrolimus levels, measured by coefficient of variability (COV), does not reliably detect nonadherence in kidney transplant patients. However, COV may indicate issues with blood work adherence or treatment response.
Area of Science:
- Nephrology
- Transplant Medicine
- Pharmacology
Background:
- Increased intrapatient variability (IPV) in tacrolimus levels is linked to adverse transplant outcomes, including graft rejection and loss.
- Medication nonadherence is a potential major driver of high tacrolimus IPV.
Purpose of the Study:
- To assess the utility of tacrolimus IPV, specifically the coefficient of variability (COV), in identifying nonadherence among kidney transplant recipients.
- To examine the correlation between self-reported medication adherence and tacrolimus COV.
Main Methods:
- Retrospective cohort study involving kidney transplant patients prescribed tacrolimus.
- Self-reported adherence assessed using a modified Basel Assessment of Adherence to Immunosuppressive Medications Scale (BAASIS).
- Tacrolimus trough level COV calculated and correlated with adherence data; median COV used to categorize patients.
Main Results:
- Of 525 patients with calculable COV, 92.38% reported adherence.
- No significant difference in COV was found between self-reported adherent (25.2%) and nonadherent (29.6%) patients (P = .2).
- Younger age correlated significantly with nonadherence and with nonadherence to routine blood work (P = .01 and P < .01, respectively).
Conclusions:
- Tacrolimus COV alone is insufficient for determining medication adherence.
- COV may offer insights into nonadherence with blood work or identify patients requiring medication adjustment due to poor response.
- Limitations include a modified, non-validated adherence questionnaire and potential biases.
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