[Double-antibody sandwich method versus indirect method of ELISA for detection of prostatic exosomal protein in the urine].

Objective: To compare two ELISA methods for the detection of the prostatic exosomal protein (PSEP) in the urine.

Methods: Using the double-antibody sandwich (DAS) method and the indirect method of ELISA, we detected PSEP in the urine samples from 100 IIIA chronic prostatitis (CP) patients and another 100 normal healthy males. Meanwhile, we examined 30 clinical urine samples using the diluent (0.1 mol/L PBS buffer) and the urine matrix standard curves to verify the consistency of the standard diluent with the sample collected. Result: The sensitivities of DAS and indirect ELISA were 89% versus 87% and their specificities 91% versus 90%, with total consistency rates of 90% versus 88.5%, with no statistically significant difference in between. The scatter plot for the results of the PBS diluent and the urine matrix standard curves showed a good linearity (R2 = 0.999). No significant difference was found in the results of detection of the clinical urine samples in different matrices.

Conclusions: Considering the characteristics of PSEP, the indirect ELISA method is more practical and feasible for the clinical detection of PSEP in the urine samples of prostatitis patients.