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Abstract: SA-PO014

Investigating Use of the Biodesix Microsampling Device for Longitudinal Biomarker Studies in Glomerulonephritis (GN) and Renal Transplantation

Session Information

Category: Bioengineering

  • 400 Bioengineering

Authors

  • Anwari, Kashif Jamil, University College London, London, United Kingdom
  • Salama, Alan D., University College London, London, United Kingdom
Background

There has been an increase in the availability of devices allowing home testing of urine, blood and most recently NP aspirates. Biodesix is a lateral flow microsampling device that has been validated in the performance of proteomics, and potentially could be used by patients at home to collect blood and urine, then sent by post for subsequent analysis. We studied whether this device could be used to identify changes in patients with a) GN flares using urine (normalized CD-163) and blood (PR3 antibody and serum-PR3 antigen levels) and b) renal transplant dysfunction (DSA), by comparing with conventional methods of isolating serum and urine.

Methods

Following ethical approval and informed consent, blood/urine samples were obtained from patients with GN (during disease flare and remission) and from renal transplant patients with positive anti-HLA antibodies and CRF >90%. 250uL of sample was placed on a biodesix paper and incubated at room temperature for 5-10 days. The plasma component of the biodesix paper was treated in a standardized manner, reconstituted with 500uL PBS, vortexed for 5 minutes and then centrifuged in 0.45um spin filters for 3 minutes. Samples were analyzed using commercially available ELISA kits and via Luminex (DSA). Biodesix samples were compared with centrifuged blood/urine.

Results

All patients with active GN (n=7) demonstrated raised normalized-CD163 levels with the biodesix device that were comparable with standard urine isolation (p=0.17). Serum and biodesix samples showed concordance with PR3-antibody levels (n=3, p=0.40) and serum-PR3 antigen levels (n=4, p=0.49), and similar results were noted between biodesix samples processed at various time points after blood collection (3, 10 or 90 days). Luminex revealed near identical HLA profiles for biodesix samples vs whole blood in transplant patients (n=4), but MFI values were significantly lower for former.

Conclusion

We have demonstrated that the biodesix device can provide comparable data to standard urine/blood analysis, and potentially be used to identify GN flares and development of de novo DSAs. These devices provide potential benefits including patient convenience, ability to perform more frequent monitoring with earlier detection, and access to a wider patient cohort for biobanking. Further work to validate the biodesix device in these cohorts is required.