Abstract
Background: Variation in performance of glomerular filtration rate (GFR) estimating equations is related to variation in calibration of the creatinine assay across clinical laboratories. Study Design: Cross-sectional analysis. Setting & Participants: 6 research studies and 4 clinical populations including 5,504 participants who had GFR measured using urinary clearance of iothalamate. Measurements: Standardized serum creatinine values obtained by means of calibration to the Cleveland Clinic Research Laboratory using frozen specimens, a calibration panel, and/or survey results from the College of American Pathologists. Predictor: Noncalibrated serum creatinine assayed in research and clinical laboratories compared with standardized serum creatinine. Outcome: Difference between measured GFR versus GFR estimated from the Modification of Diet in Renal Disease (MDRD) Study and Cockcroft-Gault equations. Results: For a noncalibrated serum creatinine value of 1 mg/dL (88.4 μmol/L), standardized serum creatinine value was 0.07 mg/dL (6.2 μmol/L) less than noncalibrated values. In the pooled data set, for the MDRD Study equation, calibration improved median percentage of difference between measured and estimated GFR from 9.0% (interquartile range [IQR], 28%) to 5.8% (IQR, 28%) and improved the percentage of estimates within 30% of measured GFR (P30) from 80% to 83%. The effect of calibration was greater at higher levels of GFR and varied across studies. For the Cockcroft-Gault equation, calibration worsened the median percentage of difference from -2.0% (IQR, 38%) to -11.4% (IQR, 39%), and the P30, from 74% to 69%. Limitations: College of American Pathologist samples were used for calibration of clinical populations; calibration factors do not account for drift over time in the serum creatinine assay; calibration cannot account for variation in assay performance among individuals. Conclusion: Calibration improves the performance of the MDRD Study equation. After calibration, larger errors remain for GFR estimates greater than 60 mL/min/1.73 m2 (>1 mL/s/1.73 m2).
| Original language | English (US) |
|---|---|
| Pages (from-to) | 21-35 |
| Number of pages | 15 |
| Journal | American Journal of Kidney Diseases |
| Volume | 50 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jul 1 2007 |
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Keywords
- Chronic kidney disease
- Cockcroft-Gault equation
- Modification of Diet in Renal Disease Study equation
- calibration
- creatinine
- estimated glomerular filtration rate
- glomerular filtration rate
- individual patient meta-analysis
Cite this
Impact of Creatinine Calibration on Performance of GFR Estimating Equations in a Pooled Individual Patient Database. / Stevens, Lesley A.; Manzi, Jane; Levey, Andrew S.; Chen, Jing; Deysher, Amy E.; Greene, Tom; Poggio, Emilio D.; Schmid, Christopher H.; Steffes, Michael W; Zhang, Yaping (Lucy); Van Lente, Frederick; Coresh, Josef.
In: American Journal of Kidney Diseases, Vol. 50, No. 1, 01.07.2007, p. 21-35.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Impact of Creatinine Calibration on Performance of GFR Estimating Equations in a Pooled Individual Patient Database
AU - Stevens, Lesley A.
AU - Manzi, Jane
AU - Levey, Andrew S.
AU - Chen, Jing
AU - Deysher, Amy E.
AU - Greene, Tom
AU - Poggio, Emilio D.
AU - Schmid, Christopher H.
AU - Steffes, Michael W
AU - Zhang, Yaping (Lucy)
AU - Van Lente, Frederick
AU - Coresh, Josef
PY - 2007/7/1
Y1 - 2007/7/1
N2 - Background: Variation in performance of glomerular filtration rate (GFR) estimating equations is related to variation in calibration of the creatinine assay across clinical laboratories. Study Design: Cross-sectional analysis. Setting & Participants: 6 research studies and 4 clinical populations including 5,504 participants who had GFR measured using urinary clearance of iothalamate. Measurements: Standardized serum creatinine values obtained by means of calibration to the Cleveland Clinic Research Laboratory using frozen specimens, a calibration panel, and/or survey results from the College of American Pathologists. Predictor: Noncalibrated serum creatinine assayed in research and clinical laboratories compared with standardized serum creatinine. Outcome: Difference between measured GFR versus GFR estimated from the Modification of Diet in Renal Disease (MDRD) Study and Cockcroft-Gault equations. Results: For a noncalibrated serum creatinine value of 1 mg/dL (88.4 μmol/L), standardized serum creatinine value was 0.07 mg/dL (6.2 μmol/L) less than noncalibrated values. In the pooled data set, for the MDRD Study equation, calibration improved median percentage of difference between measured and estimated GFR from 9.0% (interquartile range [IQR], 28%) to 5.8% (IQR, 28%) and improved the percentage of estimates within 30% of measured GFR (P30) from 80% to 83%. The effect of calibration was greater at higher levels of GFR and varied across studies. For the Cockcroft-Gault equation, calibration worsened the median percentage of difference from -2.0% (IQR, 38%) to -11.4% (IQR, 39%), and the P30, from 74% to 69%. Limitations: College of American Pathologist samples were used for calibration of clinical populations; calibration factors do not account for drift over time in the serum creatinine assay; calibration cannot account for variation in assay performance among individuals. Conclusion: Calibration improves the performance of the MDRD Study equation. After calibration, larger errors remain for GFR estimates greater than 60 mL/min/1.73 m2 (>1 mL/s/1.73 m2).
AB - Background: Variation in performance of glomerular filtration rate (GFR) estimating equations is related to variation in calibration of the creatinine assay across clinical laboratories. Study Design: Cross-sectional analysis. Setting & Participants: 6 research studies and 4 clinical populations including 5,504 participants who had GFR measured using urinary clearance of iothalamate. Measurements: Standardized serum creatinine values obtained by means of calibration to the Cleveland Clinic Research Laboratory using frozen specimens, a calibration panel, and/or survey results from the College of American Pathologists. Predictor: Noncalibrated serum creatinine assayed in research and clinical laboratories compared with standardized serum creatinine. Outcome: Difference between measured GFR versus GFR estimated from the Modification of Diet in Renal Disease (MDRD) Study and Cockcroft-Gault equations. Results: For a noncalibrated serum creatinine value of 1 mg/dL (88.4 μmol/L), standardized serum creatinine value was 0.07 mg/dL (6.2 μmol/L) less than noncalibrated values. In the pooled data set, for the MDRD Study equation, calibration improved median percentage of difference between measured and estimated GFR from 9.0% (interquartile range [IQR], 28%) to 5.8% (IQR, 28%) and improved the percentage of estimates within 30% of measured GFR (P30) from 80% to 83%. The effect of calibration was greater at higher levels of GFR and varied across studies. For the Cockcroft-Gault equation, calibration worsened the median percentage of difference from -2.0% (IQR, 38%) to -11.4% (IQR, 39%), and the P30, from 74% to 69%. Limitations: College of American Pathologist samples were used for calibration of clinical populations; calibration factors do not account for drift over time in the serum creatinine assay; calibration cannot account for variation in assay performance among individuals. Conclusion: Calibration improves the performance of the MDRD Study equation. After calibration, larger errors remain for GFR estimates greater than 60 mL/min/1.73 m2 (>1 mL/s/1.73 m2).
KW - Chronic kidney disease
KW - Cockcroft-Gault equation
KW - Modification of Diet in Renal Disease Study equation
KW - calibration
KW - creatinine
KW - estimated glomerular filtration rate
KW - glomerular filtration rate
KW - individual patient meta-analysis
UR - http://www.scopus.com/inward/record.url?scp=34250783071&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34250783071&partnerID=8YFLogxK
U2 - 10.1053/j.ajkd.2007.04.004
DO - 10.1053/j.ajkd.2007.04.004
M3 - Article
VL - 50
SP - 21
EP - 35
JO - American Journal of Kidney Diseases
JF - American Journal of Kidney Diseases
SN - 0272-6386
IS - 1
ER -