engleski

ASCORBIC ACID INTERFERENCE ON THE PERFORMANCE OF ICHEM VELOCITY AND COMBUR10TEST®M URINE CHEMISTRY STRIPS

BACKGROUND-AIM: iChem Velocity (iCV) test strips manufacturer claims that ascorbic acid (AA) concentrations greater than 20 mg/dL could interfere with glucose, nitrite and blood. On the other hand, the manufacturer of Combur10Test®M (C10M) claims that AA does not interfere with glucose and blood. The aim of the study was to evaluate AA impact on the glucose, hemoglobin, nitrite and bilirubin measured with iCV and C10M urine strips. METHODS: Iris iChemVELOCITY (Iris Diagnostics, Chatsworth, USA) and Cobasu411 (Roche, Mannheim, Germany) were used to analyze associated test strips. Stock solutions of each tested analyte were prepared. The materials used were: anhydrous glucose (Kemig d.o.o), hemoglobin (whole blood) sodium nitrite (Kemika d.o.o), bilirubin (Sigma/Aldrich) and vitamin C500 (Worwag pharma GmbH&Co.KG). Specific analyte concentrations (glucose: 2.7 ; 5.8 and 16.8 mmol/L, hemoglobin: 0.03 ; 0.06 and 0.10 mg/dL, nitrite: 0.1 ; 0.2 mg/dL, bilirubin: 37 ; 70 umol/L) were prepared using negative urine pool sample and AA solution in order to achieve specific concentration in each tested sample (0 ; 20 ; 30 ; 50 ; 100 ; 200 ; 500 mg/dL). Interference was confirmed if the result was changed in comparison with pool without AA. RESULTS: AA interferes with glucose measured on C10M at 50 mg/dL and above 200 mg/dL on iCV, with hemoglobin at 20 mg/dL on both tested strips, with nitrite at 50 mg/dL on iCV and above 200 mg/dL on CM10 and with bilirubin at 50 mg/dL on both tested strips. iCV test strips are the most impacted by AA when hemoglobin, bilirubin and nitrite are tested and C10M test strips are the most impacted by AA interference when glucose, hemoglobin and bilirubin are tested. CONCLUSION: Despite manufacturers` claims our results demonstrate negative effect on tested analytes at varying concentrations of specific analyte and AA. That is why the possibility of the AA detection in urine offered by iCV could be of great help in order to avoid misdiagnosis.

ascorbic acid ; interference ; patient safety ; urinalysis

nije evidentirano