Introduction & Objective: β- hemolytic group A streptococcus is the most common cause of acute bacterial pharyngitis in children. Due to the high incidence of this disease and it's difficult diagnosis , we decided to compare clinical scoring and throat cultures for diagnosis of streptococcal pharyngitis.

Materials & Methods: This cross-sectional analytic study was done on 3-16 year old patients reffered to pediatric clinic with complaint of sore throat. After taking history and physical examination, scoring was done based on clinical findings.The patients with chronic disease or those who received antibiotics or other drugs were eliminated from the study. Analysis was performed using SPSS. Score for each patient was calculated and compared with the result of throat cultures. Sensitivity, specificity, positive and negative predictive values for each clinical finding were determined.

Results: 315 patients out of 350 patients with complaint of sore throat referred to the clinic had fever of whom 51.1% had positive throat culture with 51.1% sensitivity and 77% specifity (p<0.01). 127 patients had pharyngeal petechia of whom 67% had positive throat culture with 66.9% sensitivity and 73.5% specifity (p<0.002). 105 children had pharyngeal exudates of whom 65.7% had positive throat culture with 65.7% sensitivity and 58.3% specifity (p<0.001). Anterior cervical lymphadenopathy was detected in 293 patients of whom 53.24% had positive throat culture with 53.2% sensitivity and 73.8% specifity (p<0.002). 182 patients had no signs of upper respiratory infection, among them 65.9% had positive throat culture with 65.9% sensitivity and 70.4% specifity (p<0.001). 130 patients had sore throat, 66.3% of them had positive throat culture with 62.3% sensitivity and 59% specifity (p<0.001). 310 patients had pharyngeal erythema of which 51.6% had positive throat culture with 57.5% sensitivity and 22.7% specifity (p<0.02). 99 children had gastrointestinal signs, 66.14% had positive throat culture with sensitivity 64.6% and specifity was 58.8% (p<0.005). Headache occurred in 116 patients of whom 75.86% had positive throat culture with 75.9% sensitivity and 64.9% specifity (p<0.001). From 350 patients, in 155 children scores were equal or more than 7 of whom 83.25% had positive culture. Equal scores of 5-6 were detected in 111 patients of whom 28% had positive culture. In 84 patients scores were equal or less than 4 among them only 7% had positive culture.

Conclusion: Findings of this study showed that with increase in clinical score, the probability of positive throat culture increases. We recommend this clinical scoring system for diagnosis of streptococcal pharyngitis especially in areas where throat culture and rapid antigen detection test are not available so it can be useful for better diagnosis and reduces inappropriate antibiotic prescription.