Objective: To study the prevalence of Group A beta haemolytic Streptococcus in patients with acute pharyngitis and correlation of Modified Centor Score and Rapid Antigen Detection Test.
Methods: The multi-centre, prospective, cross-sectional study was conducted in 8 major cities of Pakistan between June 2012 and February 2013, and comprised patients presenting with acute pharyngitis. The subjects were above 3 years of age presenting to primary care physician with sore throat, temperature over 100.4 degrees F, tonsillar exudates and/or cervical adenopathy (duration of symptoms < 14 days). They were scored using Modified Centor Score and were tested with Rapid Antigen Detection Test for Group A beta haemolytic Streptococcus. SPSS 19 was used for statistical analysis.
Results: Of the 5140 patients, 1299 (25.3%) tested positive, for RADT Group A beta haemolytic Streptococcus in acute pharyngitis. There was no significant difference across different age groups (p < 0.08). There was a strong correlation between Modified Centor Score and Rapid Antigen Detection Test results (p < 0.001). Of the patients with positive result, 3 (0.4%) had a Modified Centor Score < or = 0; 23 (1.8%) had score of 1; 152 (11.7%) had score of 2; 511 (39.3%) had score of 3; and 609 (46.9%) had Centor score of > or = 4.
Conclusion: The prevalence of Group A beta haemolytic Streptococcus as a cause of acute pharyngitis was 25.3%. Modified Centor Score had a strong positive correlation with Rapid Antigen Detection Test in identifying Group A beta haemolytic Streptococcus as a cause of acute pharyngitis.