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Routine serum creatinine measurements: how well do we perform?

Hoste L, Deiteren K, Pottel H, Callewaert N, Martens F - BMC Nephrol (2015)

Bottom Line: The calculated eGFR values corresponding with the reported creatinine concentration ranges resulted in a different CKD classification in 47% of cases.The inaccuracy in the lower concentration range is of particular concern and may lead to clinical misinterpretation when the creatinine-based eGFR of the patient is used for CKD staging.Further research to improve harmonization between methods is required.

View Article: PubMed Central - PubMed

Affiliation: Interdisciplinary Research Facility Life Sciences, Katholieke Universiteit Leuven Campus Kortrijk, Kortrijk, Belgium. liesbeth.hoste@kuleuven-kulak.be.

ABSTRACT

Background: The first aim of the study was to investigate the accuracy and intra-laboratory variation of serum creatinine measurements in clinical laboratories in Flanders. The second purpose was to check the effect of this variation in serum creatinine concentration results on the calculated estimated glomerular filtration rate (eGFR) and the impact on classification of patients into a chronic kidney disease (CKD) stage.

Methods: 26 routine instruments were included, representing 13 different types of analyzers from 6 manufacturers and covering all current methodologies (Jaffe, compensated Jaffe, enzymatic liquid and dry chemistry methods). Target values of five serum pools (creatinine concentrations ranging from 35 to 934 μmol/L) were assigned by the gold standard method (ID-GC/MS).

Results: Intra-run CV (%) (n = 5) and bias (%) from the target values were higher for low creatinine concentrations. Especially Jaffe and enzymatic dry chemistry methods showed a higher error. The calculated eGFR values corresponding with the reported creatinine concentration ranges resulted in a different CKD classification in 47% of cases.

Conclusions: Although most creatinine assays claim to be traceable to the gold standard (ID-GC/MS), large inter-assay differences still exist. The inaccuracy in the lower concentration range is of particular concern and may lead to clinical misinterpretation when the creatinine-based eGFR of the patient is used for CKD staging. Further research to improve harmonization between methods is required.

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Related in: MedlinePlus

Intra-run variation of the individual analyzers for each pool according to the type of creatinine assay. Ricos-Fraser goals are presented. Solid horizontal line: minimal (<4.5%). Dashed horizontal line: desirable (<3.0%). LX20 Clinical System shows no intra-run CV within the reported precision (to the nearest tenth).
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Fig1: Intra-run variation of the individual analyzers for each pool according to the type of creatinine assay. Ricos-Fraser goals are presented. Solid horizontal line: minimal (<4.5%). Dashed horizontal line: desirable (<3.0%). LX20 Clinical System shows no intra-run CV within the reported precision (to the nearest tenth).

Mentions: In Figure 1 the CVi of the individual analyzers for each pool according to the type of creatinine assay is shown. 81% (21/26) of the analyzer results from pool 1 and 92% (24/26) of the analyzer results from pool 2 met the minimal analytical variation criterion of 4.5% (black line). For pool 3 to 5, >95% of all test results were within the minimal specification criterion. Only Jaffe and/or compensated Jaffe assays did not met the minimal specifications for pool 1 and/or 2 (lower creatinine concentrations). All enzymatic assays were within the minimal specifications.Figure 1


Routine serum creatinine measurements: how well do we perform?

Hoste L, Deiteren K, Pottel H, Callewaert N, Martens F - BMC Nephrol (2015)

Intra-run variation of the individual analyzers for each pool according to the type of creatinine assay. Ricos-Fraser goals are presented. Solid horizontal line: minimal (<4.5%). Dashed horizontal line: desirable (<3.0%). LX20 Clinical System shows no intra-run CV within the reported precision (to the nearest tenth).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4358903&req=5

Fig1: Intra-run variation of the individual analyzers for each pool according to the type of creatinine assay. Ricos-Fraser goals are presented. Solid horizontal line: minimal (<4.5%). Dashed horizontal line: desirable (<3.0%). LX20 Clinical System shows no intra-run CV within the reported precision (to the nearest tenth).
Mentions: In Figure 1 the CVi of the individual analyzers for each pool according to the type of creatinine assay is shown. 81% (21/26) of the analyzer results from pool 1 and 92% (24/26) of the analyzer results from pool 2 met the minimal analytical variation criterion of 4.5% (black line). For pool 3 to 5, >95% of all test results were within the minimal specification criterion. Only Jaffe and/or compensated Jaffe assays did not met the minimal specifications for pool 1 and/or 2 (lower creatinine concentrations). All enzymatic assays were within the minimal specifications.Figure 1

Bottom Line: The calculated eGFR values corresponding with the reported creatinine concentration ranges resulted in a different CKD classification in 47% of cases.The inaccuracy in the lower concentration range is of particular concern and may lead to clinical misinterpretation when the creatinine-based eGFR of the patient is used for CKD staging.Further research to improve harmonization between methods is required.

View Article: PubMed Central - PubMed

Affiliation: Interdisciplinary Research Facility Life Sciences, Katholieke Universiteit Leuven Campus Kortrijk, Kortrijk, Belgium. liesbeth.hoste@kuleuven-kulak.be.

ABSTRACT

Background: The first aim of the study was to investigate the accuracy and intra-laboratory variation of serum creatinine measurements in clinical laboratories in Flanders. The second purpose was to check the effect of this variation in serum creatinine concentration results on the calculated estimated glomerular filtration rate (eGFR) and the impact on classification of patients into a chronic kidney disease (CKD) stage.

Methods: 26 routine instruments were included, representing 13 different types of analyzers from 6 manufacturers and covering all current methodologies (Jaffe, compensated Jaffe, enzymatic liquid and dry chemistry methods). Target values of five serum pools (creatinine concentrations ranging from 35 to 934 μmol/L) were assigned by the gold standard method (ID-GC/MS).

Results: Intra-run CV (%) (n = 5) and bias (%) from the target values were higher for low creatinine concentrations. Especially Jaffe and enzymatic dry chemistry methods showed a higher error. The calculated eGFR values corresponding with the reported creatinine concentration ranges resulted in a different CKD classification in 47% of cases.

Conclusions: Although most creatinine assays claim to be traceable to the gold standard (ID-GC/MS), large inter-assay differences still exist. The inaccuracy in the lower concentration range is of particular concern and may lead to clinical misinterpretation when the creatinine-based eGFR of the patient is used for CKD staging. Further research to improve harmonization between methods is required.

Show MeSH
Related in: MedlinePlus