Abstract
CONTEXT.—: Use of cystatin C for glomerular filtration rate estimation (eGFR) has garnered heightened interest as a means to avoid race-based medicine, since eGFRcys equations do not require specification of race. Before considering more widespread use of cystatin C, it is important to confirm that assays provide accurate measurements of cystatin C concentration, to ensure accurate GFR estimates.
OBJECTIVE.—: To determine if the accuracy of cystatin C measurements in laboratories participating in the College of American Pathologists' (CAP) Cystatin C (CYS) survey has improved since 2014.
DESIGN.—: Two fresh frozen serum pools, the first from healthy donors without chronic kidney disease (CKD), and the second from patients with CKD, along with a synthetically prepared elevated cystatin C pool, were sent to laboratories participating in the 2019 CYS-A survey. Target values were established by using 2 immunoassays and a bracketed 2-point calibration with diluted ERM-DA471/IFCC reference material.
RESULTS.—: For the healthy donor fresh frozen pool (ERM-DA471/IFCC-traceable target of 0.725 mg/L), the all-method mean (standard deviation, coefficient of variation) was 0.731 mg/L (0.071, 9.7%). For the CKD pool (ERM-DA471/IFCC-traceable target of 2.136 mg/L), the all-method mean was 2.155 mg/L (0.182, 8.4%). For the synthetically spiked pool (ERM-DA471/IFCC-traceable target of 1.843 mg/L), the all-method mean was 1.886 mg/L (0.152, 8.1%). This represents marked improvement in accuracy and between-method agreement compared to the 2014 CAP survey.
CONCLUSIONS.—: Manufacturers have markedly improved accuracy and between-method agreement of cystatin C measurement procedures since 2014, which allows for greater confidence in estimated GFR relying on cystatin C.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1218-1223 |
| Number of pages | 6 |
| Journal | Archives of pathology & laboratory medicine |
| Volume | 146 |
| Issue number | 10 |
| Early online date | Feb 22 2022 |
| DOIs | |
| State | Published - Oct 2022 |
Bibliographical note
Funding Information:Authors received grants supporting this work from the National Institute of Diabetes and Digestive and Kidney Diseases (R01DK097020, U01DK053869, R01DK116790). Karger has received research support from Siemens Healthcare Diagnostics and is a consultant for Roche Diagnostics Corporation. The other authors have no relevant financial interest in the products or companies described in this article. The Advanced Research and Diagnostic Laboratory (ARDL) at the University of Minnesota has received free or considerably discounted reagents for measurement of cystatin C and other CKD-related biomarkers for a variety of National Institutes of Health-funded research studies from Siemens Healthcare Diagnostics.
Funding Information:
Authors received grants supporting this work from the National Institute of Diabetes and Digestive and Kidney Diseases (R01DK097020, U01DK053869, R01DK116790). Karger has received research support from Siemens Healthcare Diagnostics and is a consultant for Roche Diagnostics Corporation. The other authors have no relevant financial interest in the products or companies described in this article.
Publisher Copyright:
© 2022 College of American Pathologists. All rights reserved.
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