History and Objectives: Streptococcal pharyngitis is prevalent and without timely diagnosis and treatment of the disease, secondary side effects such as acute rheumatic fever and glumerulonephritis will ensue. In addition irrational uses of antibiotics will lead to resistance types. On the basis of WHO recommendation for the diagnosis of the infection, the present study was performed to asses the diagnostic value of clinical findings of patients referred to the Outpatient Clinic of Kashan in winter of 1996.

Materials and Methods: The present study is a diagnostic clinical trial in nature. Patient complaining from sore throat was and having a fever of 38°C or higher and having minimum of 2 sign of typical six signs (Sore throat, exudate, lymph node sensitivity, redness of throat, petechia of mouth, ulceromembranous pharyngitis) are considered as having Streptococcal pharyngitis and those with respiratory sign (Caught, roughness of voice, runny nose and conjunctivitis) are considered as viral pharyngitis. From the later group sample were taken and inoculated on blood agar culture. On the basis of clinical findings and laboratory testing, the rate sensitivity and specificity of clinical findings on the diagnosis of Streptococcus pharyngitis was assessed.

Results: From 400 cases, sensitivity of the clinical findings for the diagnosis of Streptococcus pharyngitis was 71%. Specificity, positive predictive value (Clinical value) and negative predictive values were 23, 7.8 and 89.1% respectively.

Conclusion: In light of present results, diagnosis of Streptococcus pharyngitis on the basis of clinical findings alone is not suggested. Further research into the underlying causes of poor result on the clinical diagnostic values is suggested.