BACKGROUND C-reactive protein (CRP) is an important clinical indicator. There are many methods and instruments for CRP measurement, and therefore the consistency of CRP values measured between instruments needs to be evaluated. This study aimed to compare the consistency of 3 serum CRP detection systems using turbidimetry. MATERIAL AND METHODS The consistency of CRP measured by 3 instruments, the Mindray BC-5390, Mindray BC-6800, and Johnson Vitros5600, was evaluated, and the consistency of blood routine measurement between the BC-5390 and BC-6800 was also evaluated. Pearson correlation analysis was used to evaluate the correlation of different instrument's test results (R, correlation coefficient). The consistency of instruments was assessed by Passing-Bablok analysis and weighted Deming analysis. RESULTS CRP data and route blood test data from 847 patients were used for analysis. The results showed that there were differences in the CRP values measured by the Mindray BC5390, Mindray BC6800, and Johnson Vitros5600 (χ²=78.573, P<0.001). The CRP measurement results of the BC5390 analyzer were consistent with those of the BC6800 analyzer (R=0.994, P<0.001) and Vitros5600 analyzer (R=0.983, P<0.001). However, there was a constant deviation in the CRP values measured by the BC-6800 and Vitros5600 analyzer (R=0.994, P<0.001). In the measurement of routine blood laboratory tests, the BC5390 analyzer and BC6800 analyzer were found to be interchangeable. CONCLUSIONS This study analyzed the consistency of CRP detection by 3 instruments, the Mindray BC-5390, Mindray BC-6800, and Johnson Vitros5600, and may provide a reference for the selection of CRP detection instruments.