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Abstract: SA-PO1108

Comparison of Urine and Plasma Biomarker Levels Measured by Aptamer-Based versus Immunoassay Methods in Cardiac Surgery Patients

Session Information

Category: Pathology and Lab Medicine

  • 1502 Pathology and Lab Medicine: Clinical

Authors

  • Kukova, Lidiya, Yale University, New Haven, Connecticut, United States
  • Mansour, Sherry, Yale University, New Haven, Connecticut, United States
  • Coca, Steven G., Icahn School of Medicine at Mount Sinai, New York, New York, United States
  • Thiessen Philbrook, Heather, Yale University, New Haven, Connecticut, United States
  • Shlipak, Michael, San Francisco VA Medical Center, San Francisco, California, United States
  • Parikh, Chirag R., Yale University and VAMC, New Haven, Connecticut, United States
Background

Protein-detection assays are invaluable tools in biomarker discovery. However, only immunoassays are widely used, measuring 10-20 analytes per biosample. The novel aptamer-based assay uses nucleotide aptamer technology to measure over 1,300 analytes per biosample. We sought to compare the aptamer-based platform versus traditional immunoassay approaches to quantify analytes in paired samples before and after cardiac surgery.

Methods

In a sub-study of the TRIBE-AKI cohort, 54 individuals with acute kidney injury (AKI) after cardiac surgery were identified. The group included AKI progressors and AKI non-progressors. The levels of preoperative and postoperative plasma and urine biomarkers which had been previously evaluated via immunoassays were compared to the levels detected by an aptamer-based assay using Spearman correlations.

Results

Spearman correlations were estimated when at least 50% of biomarker values were within detectable ranges (plasma: preoperative 26/33, postoperative 31/33; urine: preoperative 13/16, postoperative 16/16). Twenty seven percent of reportable plasma preoperative biomarkers displayed correlations ≥0.75 between immunoassay and aptamer measurements, 23% displayed correlations of 0.50-0.75, and 50% displayed correlations <0.50. In urine these values were 15%, 39%, and 46%, respectively. Forty two percent of reportable plasma postoperative biomarkers displayed correlations ≥0.75, 16% displayed correlations 0.50-0.75, and 42% displayed correlations <0.50. In urine these values were 19%, 25%, and 56%, respectively.

Conclusion

The aptamer-based assay detects proteins with moderate to strong correlation to current immunoassay methods. The correlations in urine are weaker compared to plasma. Aptamer-based assay technology should be further validated in multiple settings as a high-throughput screening tool for biomarker discovery.

Table 1

Funding

  • NIDDK Support