The correlation of urine protein measurement using two trichloroacetic acid and benzethonium chloride methods

Proteinuria is one of the symptoms that affects the functioning of the kidneys and 24-hour urine protein measurement is one of the key methods for diagnosis of renal failure and urinary tract infection. Investigating the relationship between the results of various methods of measuring 24-hour urine protein can increase the efficiency of proteinuria detection using these methods. Turboidometric-based methods such as trichloroacetic acid (TCA) and benzethonium chloride (BEC) are among the methods used to measure urine protein. The aim of this study was to evaluate the correlation between urine protein measurements with TCA in comparison with BEC. This study was performed on 116 patients referring to Massoud medical diagnostic laboratory in Tehran. The 24-hour urine sample were taken. Then, the amount of urine protein was measured by both TCA and BEC method at 495 and 512 nm wavelengths respectively. The results obtained using Pearson correlation test showed that the correlation coefficient for both TCA and BEC methods is 0.914 (Pvalue <0.001).  Passing and Bablok regression analysis showed that the average protein concentration of the urine with BEC method was 17.31 ± 19.81 and for the TCA method   was 17.40 ± 20.59 mg / dl. In this study, it was shown that there is no difference between the measured results in the range of 1-150 mg/dl of 24-hour urine protein with both TCA and BEC method. Also, there was a good agreement in correlation between the results of both TCA and BEC in the range of 1-150mg, and in general, the data from the two methods were in agreement with each other.