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Leion F, Hegbrant J, den Bakker E, Jonsson M, Abrahamson M, Nyman U, Björk J, Lindström V, Larsson A, Bökenkamp A, Grubb A. Estimating glomerular filtration rate (GFR) in children. The average between a cystatin C- and a creatinine-based equation improves estimation of GFR in both children and adults and enables diagnosing Shrunken Pore Syndrome. Scandinavian Journal of Clinical and Laboratory Investigation 2017; 77:338-344. [PMID: 28521564 DOI: 10.1080/00365513.2017.1324175] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Estimating glomerular filtration rate (GFR) in adults by using the average of values obtained by a cystatin C- (eGFRcystatin C) and a creatinine-based (eGFRcreatinine) equation shows at least the same diagnostic performance as GFR estimates obtained by equations using only one of these analytes or by complex equations using both analytes. Comparison of eGFRcystatin C and eGFRcreatinine plays a pivotal role in the diagnosis of Shrunken Pore Syndrome, where low eGFRcystatin C compared to eGFRcreatinine has been associated with higher mortality in adults. The present study was undertaken to elucidate if this concept can also be applied in children. Using iohexol and inulin clearance as gold standard in 702 children, we studied the diagnostic performance of 10 creatinine-based, 5 cystatin C-based and 3 combined cystatin C-creatinine eGFR equations and compared them to the result of the average of 9 pairs of a eGFRcystatin C and a eGFRcreatinine estimate. While creatinine-based GFR estimations are unsuitable in children unless calibrated in a pediatric or mixed pediatric-adult population, cystatin C-based estimations in general performed well in children. The average of a suitable creatinine-based and a cystatin C-based equation generally displayed a better diagnostic performance than estimates obtained by equations using only one of these analytes or by complex equations using both analytes. Comparing eGFRcystatin and eGFRcreatinine may help identify pediatric patients with Shrunken Pore Syndrome.
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Affiliation(s)
- Felicia Leion
- a Department of Clinical Chemistry , Skåne University Hospital, Lund University , Lund , Sweden
| | - Josefine Hegbrant
- a Department of Clinical Chemistry , Skåne University Hospital, Lund University , Lund , Sweden
| | - Emil den Bakker
- b Department of Pediatric Nephrology , VU University Medical Center , Amsterdam , The Netherlands
| | - Magnus Jonsson
- c Department of Clinical Chemistry , Skåne University Hospital , Malmö , Sweden
| | - Magnus Abrahamson
- a Department of Clinical Chemistry , Skåne University Hospital, Lund University , Lund , Sweden
| | - Ulf Nyman
- d Institution of Clinical Sciences, Malmö, Faculty of Medicine , University of Lund , Lund , Sweden
| | - Jonas Björk
- e Department of Occupational and Environmental Medicine , Lund University , Lund , Sweden
| | - Veronica Lindström
- a Department of Clinical Chemistry , Skåne University Hospital, Lund University , Lund , Sweden
| | - Anders Larsson
- f Department of Medical Sciences , Uppsala University , Uppsala , Sweden
| | - Arend Bökenkamp
- b Department of Pediatric Nephrology , VU University Medical Center , Amsterdam , The Netherlands
| | - Anders Grubb
- a Department of Clinical Chemistry , Skåne University Hospital, Lund University , Lund , Sweden
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Bargnoux AS, Piéroni L, Cristol JP, Kuster N, Delanaye P, Carlier MC, Fellahi S, Boutten A, Lombard C, González-Antuña A, Delatour V, Cavalier E. Multicenter Evaluation of Cystatin C Measurement after Assay Standardization. Clin Chem 2017; 63:833-841. [PMID: 28188233 DOI: 10.1373/clinchem.2016.264325] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 11/28/2016] [Indexed: 11/06/2022]
Abstract
BACKGROUND Since 2010, a certified reference material ERM-DA471/IFCC has been available for cystatin C (CysC). This study aimed to assess the sources of uncertainty in results for clinical samples measured using standardized assays. METHODS This evaluation was performed in 2015 and involved 7 clinical laboratories located in France and Belgium. CysC was measured in a panel of 4 serum pools using 8 automated assays and a candidate isotope dilution mass spectrometry reference measurement procedure. Sources of uncertainty (imprecision and bias) were evaluated to calculate the relative expanded combined uncertainty for each CysC assay. Uncertainty was judged against the performance specifications derived from the biological variation model. RESULTS Only Siemens reagents on the Siemens systems and, to a lesser extent, DiaSys reagents on the Cobas system, provided results that met the minimum performance criterion calculated according to the intraindividual and interindividual biological variations. Although the imprecision was acceptable for almost all assays, an increase in the bias with concentration was observed for Gentian reagents, and unacceptably high biases were observed for Abbott and Roche reagents on their own systems. CONCLUSIONS This comprehensive picture of the market situation since the release of ERM-DA471/IFCC shows that bias remains the major component of the combined uncertainty because of possible problems associated with the implementation of traceability. Although some manufacturers have clearly improved their calibration protocols relative to ERM-DA471, most of them failed to meet the criteria for acceptable CysC measurements.
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Affiliation(s)
- Anne-Sophie Bargnoux
- Laboratoire de Biochimie, CHRU de Montpellier, PhyMedExp, University of Montpellier, INSERM U1046, CNRS UMR 9214, Montpellier cedex 5, France
| | - Laurence Piéroni
- Laboratoire de Biologie Médicale, Centre Hospitalier d'Avignon, Avignon, France
| | - Jean-Paul Cristol
- Laboratoire de Biochimie, CHRU de Montpellier, PhyMedExp, University of Montpellier, INSERM U1046, CNRS UMR 9214, Montpellier cedex 5, France;
| | - Nils Kuster
- Laboratoire de Biochimie, CHRU de Montpellier, PhyMedExp, University of Montpellier, INSERM U1046, CNRS UMR 9214, Montpellier cedex 5, France
| | - Pierre Delanaye
- Department of Nephrology, Dialysis and Hypertension, University of Liege, CHU Sart-Tilman, Liege, Belgium
| | | | - Soraya Fellahi
- Laboratoire de Biochimie et Hormonologie, Hôpital tenon, APHP, Paris, France
| | - Anne Boutten
- Laboratoire de Biochimie Métabolique et Cellulaire, Hôpital Bichat-Claude Bernard, APHP, Paris, France
| | - Christine Lombard
- Laboratoire d'Immunochimie, Centre Hospitalier Lyon Sud, Pierre Bénite, France
| | - Ana González-Antuña
- Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Oviedo, Spain.,Department of Clinical Chemistry, University of Liege, CHU Sart-Tilman, Liege, Belgium
| | - Vincent Delatour
- Laboratoire National de Métrologie et d'Essais (LNE), Paris, France
| | - Etienne Cavalier
- Department of Clinical Chemistry, University of Liege, CHU Sart-Tilman, Liege, Belgium
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