INTRODUCTION

The use of different test systems in laboratories for the analysis of tumor-associated markers (TM) requires comparability of the results of their determination, especially in monitoring patients aimed at treatment effectiveness assessment and preclinical relapse detection. The purpose of this work was to compare the results of serum total prostate-specific antigen (tPSA) and CA 125 tests obtained using diagnostic kits produced by Abbott (USA) and Mindray (China).

MATERIALS AND METHODS

TM levels were measured using Architect i1000 immunoassay analyzer (Abbott). Ninety-nine sera from male patients with a tPSA level in the range from <0.008 to 256 ng/ml and 101 sera from women with a CA 125 level in the range of 4.0—3885.0 U/ml were selected for comparison with Mindray CL1200i analyzer results.

RESULTS

In the total set of observations, the median tPSA level obtained using the Abbott immunoassay was 1.45 (0.51—5.55) ng/ml, according to the Mindray immunoassay it was 1.60 (0.5—4.71) ng/ml (Spearman correlation coefficient r_S=0.954; relative bias using the Bland-Altman method was –0.11±3.94). Regarding the tPSA threshold (4.0 ng/ml) the number of discrepant conclusions was 4 out of 99 (4%) cases in the area of both low and high Abbott values. The median levels of CA 125 according to the Abbott and Mindray immunoassay were 18.4 (10.2—62.6) U/ml and 14.3 (8.1—48.4) U/ml, respectively (r_S=0.938; relative bias 10.7±86.9). The number of discrepant conclusions regarding the CA 125 threshold (35.0 ng/ml) was 6 out of 101 (6%) cases, and all cases belonged to the area of elevated Abbott values.

CONCLUSION

Mindray immunoassays provide similar results for measuring tPSA and CA 125 when compared with Abbott test-systems. When switching from one immunoassay to another in the process of the patients’ monitoring, it is necessary to make at least one measurement of TM using both test-systems to assess data equivalence.