Does C-reactive protein have a value in early detection of infection after extracorporeal shock wave lithotripsy?

Abstract

Introduction: Extracorporeal shock wave lithotripsy (ESWL) has produced a great revolution in the treatment of the urolithiasis. Bacteriemia, bacteriuria, and septic shock are the documented complaints for which early diagnosis and treatment can be vital. C-reactive protein (CRP), an acute phase reactant, serves as a marker of the infection before other measures. In this study, we measured the CRP value in the early detection of bacteriemia and bacteriuria after ESWL.

Methods: In 2005, we sought patients who had urolithiasis and were candidates for ESWL, and we recruited such patients for this study. The inclusion criteria were sterile urine and a negative CRP test. The patients who participated in the study were requested to undergo laboratory tests on the third and seventh days after ESWL. After the resulting data were entered into the SPSS-11.5 data analysis software, the analyses were done with Chi squared test.

Results: Among the studied subjects, 29 out of 97 (29.9%) had a positive CRP test and 16 (15.2%) had positive urine cultures. There was no significant statistical relationship between the CRP tests and the urine cultures (P value > 0.05). On the third day, the relationship between CRP and erythrocyte sedimentation rate (ESR) was significant (P value < 0.001). The positive predictive values of CRP were 0.087 and 0.214, and the negative predictive values were 0.87 and 0.963. The sensitivity and specificity of CRP were 18.2% and 74.1% (first stage), respectively, and 60% and 82.5% (second stage), respectively.

Conclusions: We were unable to determine what the diagnostic value of CRP should be in the early detection of infection after ESWL. Additional studies are needed to provide greater insight into this issue.