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Abstract: TH-PO825

Rapid Point-of-Care Capillary Blood Assays for Monitoring Cystatin C Levels in Kidney Transplant Recipients

Session Information

Category: Transplantation

  • 2102 Transplantation: Clinical

Authors

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

Group or Team Name

  • IOS.
Background

Frequent monitoring of tacrolimus (TAC), an FDA-approved immunosuppressant, and estimated glomerular filtration rate (eGFR) in kidney transplant recipients (KTRs) are necessary to prevent allograft rejection and toxicity. We propose to use cystatin C (CysC) concentration as a marker for estimating eGFR for KTRs; CysC concentration is independent of age, sex, and muscle mass, making it a valuable predictor of nephrotoxic risks associated with TAC in KTRs. IOS has partnered with UCI Nephrology and WFIRM to develop a novel point-of-care (POC) enhanced lateral flow assay (ELFA) platform to determine levels of CysC from fingerstick capillary blood.

Methods

ELFA performance was assessed using standard calibration curves (SCCs) with spiked whole blood samples at various CysC levels. Method validation involved 17 KTRs, comparing ELFA measurements on fingerstick blood samples (n=3) to standard lab measurements of CysC from venous blood. Samples were collected from the same KTRs before their next TAC dose. A comparison of ELFA CysC and lab serum assumed a 50% hematocrit correction. Pearson correlation and Bland-Altman analysis determined the agreement between ELFA and clinical laboratory methods.

Results

SCCs indicated ELFA performs well in the 0-6 mg/L range for CysC. ELFA and standard lab measurements strongly correlated with r=0.88. Bland-Altman analysis showed a mean difference (bias) of 0.13 mg/L for CysC between the two methods.

Conclusion

The ELFA platform delivers minimally invasive, convenient sampling in a POC device using capillary fingerstick blood from KTRs, and provides accurate, rapid measurements of CysC that have demonstrated good repeatability and strong correlation with laboratory standard reference measurements.

Funding

  • Other U.S. Government Support