Abstract: SA-PO402
Impact of Inter-Laboratory Variability of Serum Creatinine Assays on KFRE Risk Scores
Session Information
- CKD: Estimating Equations, Incidence, Prevalence, Special Populations
November 04, 2017 | Location: Hall H, Morial Convention Center
Abstract Time: 10:00 AM - 10:00 AM
Category: Chronic Kidney Disease (Non-Dialysis)
- 302 CKD: Estimating Equations, Incidence, Prevalence, Special Populations
Authors
- Jalan, Divyanshi, Queen's University School of Medicine, Kingston, Ontario, Canada
- Lee, Elizabeth S., University of British Columbia, Vancouver, British Columbia, Canada
- Collier, Christine P., Queen's University, Kingston, Ontario, Canada
- Akbari, Ayub, University of Ottawa, Ottawa, Ontario, Canada
- White, Christine A., Queen's University, Kingston, Ontario, Canada
Background
Inter-laboratory variation in creatinine (Cr) measurement exist and result in inter-laboratory variability in eGFR-EPI and chronic kidney disease (CKD) diagnosis. We aim to examine the impact of inter-laboratory variability in Cr measurement on the Kidney Function Risk Equation (KFRE).
Methods
Split serum samples from 33 patients with eGFR-EPI between 10 and 60 ml/min/1.73m2 were sent to 12 laboratories for Cr measurement. For each patient and laboratory we calculated the 5 year risk of ESKD using the KFRE equation (KFRE-5) assuming 65 year old non-African American woman and three ACR levels (27, 266, 885 mg/g). For each patient and ACR value we calculated the KFRE-5 all method mean (AMM), coefficient of variation (CVa) and range. For the cohort, we determined the mean KFRE-5 range, CVa and the mean ratio of minimum and maximum KFRE-5 scores.
Results
Figure 1 shows individual patients’ mean, minimum and maximum KFRE-5 scores (ACR 266 mg/g). There is substantial variability in KFRE scores which are more pronounced with higher albuminuria and when KFRE values are between 5% and 80% [Table 1, Figure 1].
Conclusion
Inter-laboratory variability of serum Cr measurement results in variability in KFRE scores which is more pronounced when eGFR is moderately-severely reduced and ACR is high. This needs to be considered when using KFRE cut-offs for referrals, clinic discharge, vascular access placement and suitability for CKD funding. Manufacturers need to improve assay specificity in order to reduce KFRE variability between laboratories.
Table 1: Mean ± SD KFRE-5 range and max/min ratios
ACR 27 mg/g | ACR 266 mg/g | ACR 885 mg/g | |
KFRE-5 range (mean ± SD) (%) | 2.9 ± 2.4 | 6.3 ± 4.5 | 8.4 ± 5.7 |
KFRE-5 CVa (mean ± SD) (%) | 20.8 ± 11.3 | 19.9 ± 11.6 | 19.0 ± 12.0 |
KFRE-5 max/min (mean ± SD) | 2.4 ± 1.2 | 2.3 ± 1.2 | 2.3 ± 1.2 |
Figure 1: Individual patients’ mean, minimum and maximum KFRE-5 scores (ACR 266 mg/g)
Funding
- Private Foundation Support