[HTML][HTML] Accuracy of determination of the glomerular filtration marker iohexol by European laboratories as monitored by external quality assessment
G Nordin, S Ekvall, C Kristoffersson… - Clinical Chemistry and …, 2019 - degruyter.com
G Nordin, S Ekvall, C Kristoffersson, AS Jonsson, SE Bäck, N Rollborn, A Larsson
Clinical Chemistry and Laboratory Medicine (CCLM), 2019•degruyter.comBackground Glomerular filtration is the most important kidney function. The most accurate
glomerular filtration rate (GFR) estimates are based on the clearance of exogenous filtration
markers. Of these, iohexol is the only exogenous marker that is included in an external
quality assessment (EQA) scheme. The aim of the present study was to evaluate the
performance of the European laboratories participating in Equalis' EQA scheme for iohexol.
Methods Weighed amounts of iohexol (Omnipaque) were added to plasma samples and …
glomerular filtration rate (GFR) estimates are based on the clearance of exogenous filtration
markers. Of these, iohexol is the only exogenous marker that is included in an external
quality assessment (EQA) scheme. The aim of the present study was to evaluate the
performance of the European laboratories participating in Equalis' EQA scheme for iohexol.
Methods Weighed amounts of iohexol (Omnipaque) were added to plasma samples and …
Background
Glomerular filtration is the most important kidney function. The most accurate glomerular filtration rate (GFR) estimates are based on the clearance of exogenous filtration markers. Of these, iohexol is the only exogenous marker that is included in an external quality assessment (EQA) scheme. The aim of the present study was to evaluate the performance of the European laboratories participating in Equalis’ EQA scheme for iohexol.
Methods
Weighed amounts of iohexol (Omnipaque) were added to plasma samples and distributed to laboratories participating in the EQA scheme for iohexol. All laboratories performed the assays in a blinded fashion.
Results
The number of participating laboratories varied between 27 and 34 during the study period. Iohexol was determined by HPLC in 77% of the laboratories and by UPLC/MS/MS methods in 15% of the laboratories. The mean interlaboratory coefficient of variation was 4.7% for the HPLC methods and 6.4% for the UPLC/MS/MS methods. The mean bias between calculated and measured iohexol values was –1.3 mg/L (95% confidence interval ±0.3) during the first part of the study period and 0.1 mg/L (±0.3) during the later part.
Conclusions
The low interlaboratory variation demonstrates that iohexol can be measured reliably by many laboratories and supports the use of iohexol as a GFR marker when there is a need for high quality GFR measurements.
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