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Abstract: SA-PO1025

Significance of Single-Point Cystatin C Measurement

Session Information

Category: Pathology and Lab Medicine

  • 1800 Pathology and Lab Medicine

Authors

  • Ejaz, Abutaleb Ahsan, University of Maryland Baltimore, Baltimore, Maryland, United States
  • Fisher, Evan I., University of Maryland Baltimore, Baltimore, Maryland, United States
  • Atefi, Nazli, University of Maryland Baltimore, Baltimore, Maryland, United States
  • Haq, Zain, University of Maryland Baltimore, Baltimore, Maryland, United States
  • Moody, Taylor R., University of Maryland Baltimore, Baltimore, Maryland, United States
  • Seliger, Stephen L., University of Maryland Baltimore, Baltimore, Maryland, United States
Background

Single-point serum Cystatin C in the absence of prior reference points has resulted in difficulties in interpretation of changes in kidney function. We investigated the correlation between Cystatin C and prior year change in creatinine (SCR) based eGFR for which multiple datapoints were available.

Methods

Simultaneously measured SCR and Cystatin C and their respective eGFRs were analyzed.

Results

33 SCR-Cystatin C pairs were available for analysis. Patient characteristics included: mean age 72.1+8.7 years, 90.9% male gender, 84.8% African American race, prevalence of hypertension 90.9%, diabetes 48.4%, BMI 28.8+6.2, SCR 2.1+0.8mg/dL, eGFR CKD-EPI 41.8+14.9mL/min, Cystatin C 2.1+0.7mg/dL and Cystatin-eGFR 35.6+14.6mL/min. The mean difference in SCR-Cystatin was 0.00+0.41mg/dL. Mean rate of prior year eGFR decline was 2.4+4.1mL/min/year. SCR-Cystatin C demonstrated good correlation, as did eGFR CKD-EPI and Cystatin-eGFR. Although statistically significant, Cystatin C and prior year eGFR CKD-EPI changes demonstrated poor correlation. There were no significant correlation between delta SCR-Cystatin and delta eGFR CKD-EPI – Cystatin eGFR, Cystatin-BMI. Significant inverse correlation was observed between Cystatin C and eGFR CKD-EPI (R2=0.69, p<0.001.

Conclusion

In a small sample of CKD patients, serum Cystatin C, while well correlated with simultaneously measured SCR and GFR, was a poor indicator of prior year change in GFR.

Serum creatinine, Cystatin C and eGFRs

Funding

  • Veterans Affairs Support