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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

Bias of the individual analyzers for each pool according to the type of creatinine assay. Ricos-Fraser goals are presented. Solid horizontal line: minimal (<5.9%). Dashed horizontal line: desirable (<4.0%).
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Fig2: Bias of the individual analyzers for each pool according to the type of creatinine assay. Ricos-Fraser goals are presented. Solid horizontal line: minimal (<5.9%). Dashed horizontal line: desirable (<4.0%).

Mentions: In Figure 2 the bias of the individual analyzers for each pool according to the creatinine assay type is presented. The pool with the lowest creatinine concentration (pool 1) has the largest bias for almost all analyzers. For this pool, 62% (16/26) of the analyzers failed to reach the minimal bias specification of 5.9% (black line). Some Jaffe methods (Dimension Vista 1500 (Siemens) and the two Architect C16000 analyzers (Abbott)) gave very large biases (up to 30%). Also all dry chemistry analyzers (n = 3) (Ortho Clinical Diagnostics Inc.) showed unacceptable positive biases for pool 1 according to Ricos-Fraser. For pool 2, 77% (20/26) of all methods met the minimal bias specifications (<5.9%), but only 50% (13/26) met the desirable bias criterion (<4.0%). For pool 3–5 which are in the adult pathological range, respectively 100%, 88% and 100% of the analyzers met the minimal bias specification. The liquid enzymatic assays (n = 8) have the best score over the whole concentration range, although for pool 1 they all showed negative biases. Moreover, 5 out of 8 of these negative biases are unacceptable.Figure 2


Routine serum creatinine measurements: how well do we perform?

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

Bias of the individual analyzers for each pool according to the type of creatinine assay. Ricos-Fraser goals are presented. Solid horizontal line: minimal (<5.9%). Dashed horizontal line: desirable (<4.0%).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig2: Bias of the individual analyzers for each pool according to the type of creatinine assay. Ricos-Fraser goals are presented. Solid horizontal line: minimal (<5.9%). Dashed horizontal line: desirable (<4.0%).
Mentions: In Figure 2 the bias of the individual analyzers for each pool according to the creatinine assay type is presented. The pool with the lowest creatinine concentration (pool 1) has the largest bias for almost all analyzers. For this pool, 62% (16/26) of the analyzers failed to reach the minimal bias specification of 5.9% (black line). Some Jaffe methods (Dimension Vista 1500 (Siemens) and the two Architect C16000 analyzers (Abbott)) gave very large biases (up to 30%). Also all dry chemistry analyzers (n = 3) (Ortho Clinical Diagnostics Inc.) showed unacceptable positive biases for pool 1 according to Ricos-Fraser. For pool 2, 77% (20/26) of all methods met the minimal bias specifications (<5.9%), but only 50% (13/26) met the desirable bias criterion (<4.0%). For pool 3–5 which are in the adult pathological range, respectively 100%, 88% and 100% of the analyzers met the minimal bias specification. The liquid enzymatic assays (n = 8) have the best score over the whole concentration range, although for pool 1 they all showed negative biases. Moreover, 5 out of 8 of these negative biases are unacceptable.Figure 2

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