| Objective: We inquire into assess the clinical validation of polymerase chain reaction (PCR) assay for diagnosis of pertussis. Methods: Depending on selected and excluded criterion, we choosed 163 cases from patients seeking medical advice in our hospital and 34 people in contact with definitive pertussis patients. Nasopharyngeal swabs were taked from all 197 patients for PCR detecting two B.pertussis gene targets (pertussis toxin S1 promoter and the insertion element IS481) and bacterial culture. The same amount of sera were measured pertussis toxin (PT) IgG and filamentous hemaglutinin (FHA) IgG by ELISA assay. While definitive cases were regarded as the "Golden standard", 26 cases were diagnosed as having pertussis, and 171 cases were without pertussis. These 171 cases of non-pertussis served as control cases. Compared to pertussis cases, we evaluate the clinical usefulness of PCR detecting two B. pertussis gene targets as a diagnostic tools. Results: There were 22 cases (84.62%) which had PCR positive results in the pertussis cases group, and 2 cases (1.18%) in the control group. The sensitivity, specificity, positive predictive value and positive likelihood radio of the PCR were 84.62%, 98.83%, 91.67%, 72.32. Conclusion: Our findings show that PCR demonstrated a significant improvement in diagnostic yield over culture. The PCR assay proved highly sensitive, specific technique for the diagnosis of pertussis. PCR is a rapid, useful, sensitive and practical technique, together with serological assays, can enhance surveil- lance level for pertussis in all age groups. |
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