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Published on: November 8, 2015
Minimally Invasive Therapeutic Drug Monitoring of Immunosuppressants in Children with Kidney Diseases: Validation of
Marika Ishii1, Jun Aoyagi1, Natsuka Kimura2
1Department of Pediatrics, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke 329-0498, Tochigi, Japan.
Insights
Minimally invasive fingerstick blood tests accurately measure immunosuppressant drug levels in children, offering a less burdensome alternative to traditional venous draws for therapeutic drug monitoring.
Area of Science:
- Pharmacology
- Pediatric Nephrology
- Analytical Chemistry
Background:
- Therapeutic drug monitoring (TDM) of immunosuppressants is crucial for pediatric kidney disease management.
- Repeated venipuncture for TDM poses a significant burden on pediatric patients.
- Evaluating less invasive sampling methods is essential to improve patient compliance and reduce procedural stress.
Purpose of the Study:
- To assess the analytical comparability of immunosuppressant drug concentrations measured from minimally invasive fingerstick capillary blood samples versus conventional venous blood samples.
- To determine the reliability of using microvolume capillary sampling for therapeutic drug monitoring in pediatric patients.
Main Methods:
- Collected 2.8 µL of capillary whole blood via fingersticks from pediatric patients on immunosuppressants.
- Quantified drug concentrations (mycophenolate mofetil, tacrolimus, cyclosporine A) using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method.
- Compared capillary results with conventional venous samples using linear regression and Bland-Altman analyses.
Main Results:
- Strong correlations (R² > 0.90) were observed between capillary and venous samples for mycophenolic acid, tacrolimus, and cyclosporine A.
- Hematocrit correction enhanced agreement for mycophenolic acid measurements.
- Bland-Altman analyses indicated acceptable bias, supporting the analytical reliability of capillary sampling.
Conclusions:
- Fingerstick-based microvolume sampling coupled with LC-MS/MS offers a reliable method for immunosuppressant quantification in pediatric patients.
- This minimally invasive approach has the potential to reduce procedural burden and facilitate outpatient or home-based TDM strategies.
- Further clinical validation is warranted to fully integrate this method into routine pediatric care.
Abstract:
Background/Objectives: Therapeutic drug monitoring (TDM) of immunosuppressants is essential in treating pediatric kidney diseases; however, repeated venipuncture is burdensome in children. We evaluated whether minimally invasive fingerstick capillary sampling combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) provides results analytically comparable to those of conventional venous sampling. Methods: Capillary whole blood (2.8 µL) was collected via fingersticks from pediatric patients receiving mycophenolate mofetil, with or without tacrolimus (TAC) or cyclosporine A (CsA). Drug concentrations were quantified using a previously validated simultaneous LC-MS/MS method and compared with conventional venous sampling using linear regression and Bland-Altman analyses. Results: Seventy-four paired samples from 21 patients were analyzed. Strong correlations were observed between capillary and venous samples for mycophenolic acid (MPA), TAC, and CsA (R2 > 0.90). Hematocrit correction improved agreement for MPA. Bland-Altman analyses demonstrated acceptable bias across analytes. Conclusions: Fingerstick-based microvolume sampling combined with LC-MS/MS provides analytically reliable immunosuppressant quantification in pediatric patients. Although larger clinical validation is required, this minimally invasive approach may reduce procedural burden and may support future outpatient or home-based TDM strategies.
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