Diagnostic Accuracy of Quick Stick for Identifying Traumatic Patients in Need of Tetanus Prophylaxis; a Cross-sectional Study

INTRODUCTION Based on the existing studies, measuring serum level of immunoglobulin for making decisions regarding prescription of tetanus prophylaxis seems logical and cost effective. Therefore, the present study was done with the aim of evaluating the diagnostic accuracy of tetanus quick stick (TQS) in comparison with ELISA method in this regard. METHODS The present diagnostic accuracy study was carried out on trauma patients presenting to emergency department, who were in need of receiving tetanus prophylaxis due to dirty wounds or injuries. Patients' blood was evaluated regarding presence of anti-tetanus antibody via TQS and ELISA methods and screening performance characteristics of TQS in identifying the cases in need of receiving prophylaxis was calculated compared to ELISA as the reference test. RESULTS 148 patients with the mean age of 34.58 ± 15.86 years (4-86) were studied (87.8% male). Agreement rate between the results of TQS and ELISA was 0.78 based on calculation of kappa coefficient. Sensitivity, specificity and area under the ROC curve of TQS were estimated to be 100 (95% CI: 96.50 - 100), 66.66 (95% CI: 38.68 - 86.01), and 0.83 (95% CI: 0.68 - 0.98), respectively. If TQS was used, the cost of treatment regarding use of tetabulin could have a 91.7% reduction. CONCLUSION Based on the findings of the present study, TQS has good diagnostic accuracy in comparison with ELISA and considering its 100% sensitivity and negative predictive value in cases with dirty wound, it can be considered as a reliable tool for screening patients that do not need to receive anti-tetanus prophylaxis.