Volume : 2, Issue : 2, JAN 2018

Comparison study: two methods for determination of urinary citrate



Objective: Measurements of urinary citrate is considered as an indicator of the risk for kidney stone formation, in this study we compared two methods of urinary citrate assessment, and these methods are colorimetric method and enzymatic method.

Methods: urinary citrate levels were determined by a colorimetric method and a commercially enzymatic method in patients with urolithiasis (n= 60) and in healthy controls (n=40).performance characteristics of both methods were compared.

Results: In comparison with the urinary citrate levels of healthy controls the urinary citrate levels in patients with urolithiasis were lower. The difference between patients and controls was insignificant by enzymatic method, were it was significant by colorimetric method. Low, intermediate and high citrate containing urinary pool within- run imprecision for colorimetric method were,2.0,2.75and 3.25, and 3.1,3.4 and 4.5for enzymatic method, run to run imprecision studies for colorimetric method were 5.0, 6.0 and 6.75 and 7.0,7.75and 8.75 for enzymatic method. Enzymatic method was linear up to 5mmol/L while colorimetric method was linear up to 10 m mol/L. The detection of limit of colorimetric method and enzymatic method was 0.09 μ mol/L and 0.375μ mol/L; mean recoveries were 93%and 87% respectively. There is a positive, strong (good) and statistically significant correlation between enzymatic and calorimetric measures (r=0.853, p<0.001).

Conclusion: according to the pervious results the colorimetric method has superiority in comparison with enzymatic method.


Citrate, Urolithiasis, Colorimetric And Enzymatic.

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