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Abstract: FR-PO800

A Novel, Sensitive Assay for Rapid Point of Care Monitoring of Tacrolimus Level in Capillary Blood of Kidney Transplant Recipients

Session Information

Category: Transplantation

  • 2002 Transplantation: Clinical

Authors

  • Kalantar-Zadeh, Kamyar, University of California, Irvine, Irvine, California, United States
  • Nguyen, Trong, Intelligent Optical Systems, Inc., Torrance, California, United States
  • Ortega, Maria, Intelligent Optical Systems, Inc., Torrance, California, United States
  • Kulahci, Yalcin, Wake Forest for Regenerative Medicine, Winston-Salem, North Carolina, United States
  • Zor, Fatih, Wake Forest for Regenerative Medicine, Winston-Salem, North Carolina, United States
  • Gorantla, Vijay S., Wake Forest for Regenerative Medicine, Winston-Salem, North Carolina, United States
  • Daza Aguilar, Andrea C., University of California, Irvine, Irvine, California, United States
  • Tantisattamo, Ekamol, University of California, Irvine, Irvine, California, United States
  • Reddy, Uttam Gummadi, University of California, Irvine, Irvine, California, United States
  • Rhee, Connie, University of California, Irvine, Irvine, California, United States
  • Ganguli, Rahul, Intelligent Optical Systems, Inc., Torrance, California, United States
Background

Frequent monitoring of immunosuppression in kidney transplant recipients (KTRs) is needed to prevent allograft rejection and toxicity, This is due to the short therapeutic window and the differences in pharmacokinetics/-dynamics across KTRs. Intelligent Optical Systems (IOS) has partnered with the University of California Irvine (UCI) Nephrology and Wake Forest Institute for Regenerative Medicine to develop a novel enhanced lateral flow assay (ELFA) platform, with a point-of-care (POC) assay, to determine tacrolimus (TAC) levels from fingerstick capillary blood.

Methods

We performed assay validations for ELFA using spiked whole blood, and then clinical validation using whole blood from 16 KTRs. For technical validation we assessed intra-/inter-assay repeatability based on CV% across measurements of samples spiked at different TAC levels. Each sample was measured with five replicates (n=5) to obtain CV% values. We also built a standard calibration curve (SCC) with n=3 for each level of the relevant ranges to determine the TAC levels from ELFA readouts from KTR samples. ELFA TAC measurements, n=3, of capillary blood from fingerstick were compared to LC-MS measurements of venous blood collected from the same patient immediately before the KTR's next dose of TAC. Pearson correlation was used to estimate ELFA and LC-MS correlations.

Results

Inter-/intra-assay assessment with spiked human whole blood demonstrated good repeatability, with CV ≤ 10%. SCCs indicated the assay has good performance in the range from 0-30 ng/ml, with limit of detection of 1 ng/ml. ELFA and LCMS measurements showed strong correlation (r = 0.89) for blood samples from KTRs (figure).

Conclusion

The ELFA platform is a minimally invasive, convenient sampling POC device using capillary fingerstick blood, and provides accurate, rapid measurements of TAC, which demonstrate good repeatability and strong correlation against LC-MS standard reference measurements.

Funding

  • Other U.S. Government Support