Related Experiment Video
Updated: Jun 27, 2026

Rapid Molecular Detection and Differentiation of Influenza Viruses A and B
Published on: January 30, 2017
[Validation of a rapid antigenic test in the diagnosis of pharyngitis caused by group a beta-haemolytic
Carles Llor1, Silvia Hernández Anadón, Frederic Francesc Gómez Bertomeu
1Medicina de Familia, Centro de Salud Jaume I, Tarragona, Spain. carles.llor@urv.cat
Objective:
To determine the validity of the rapid antigen test (RAT) OSOM StrepA Genzyme for the diagnosis of acute pharyngitis caused by group A beta-haemolytic strep (GABHS).
Design:
Diagnostic techniques survey.
Setting:
Urban primary care centre, Spain.
Participants:
All patients over 14 years old seen in 6 surgeries with sore throat and 2 or more Centor criteria: pharyngotonsillar exudate, tender laterocervical nodes, absence of coughing, and/or history or presence of fever.
Principal Measurements:
Pharyngeal swabs were taken from all the patients, one for RAT and another to send for culture in the microbiology department.
Results:
A total of 182 patients were evaluable, with a mean age of 30.6 (12.1) years of which 116 were women (63.7%); 63 patients had 2 Centor criteria; 83 had 3 and 36, the 4 criteria. The culture was positive in 102 patients (56%), with GABHS showing infection in forty (22%; 95% confidence interval [CI], 21.2-22.8). Group C Streptococcus was isolated in 26 patients (14.3%). GABHS was higher among patients with four Centor criteria (38.9% vs 25.3% observed among those with 3 criteria and 7.9% with 2 criteria; P<.001). Sensitivity of RAT was 95%, with a specificity of 93%, a positive predictive value of 79.2% and a negative predictive value of 98.5%.
Conclusions:
These results show the usefulness of RAT for diagnosing streptococcal pharyngitis. Its use should be spread to all primary care practices.
Related Concept Videos
Acute Pharyngitis
Acute pharyngitis is the inflammation of the back of the throat (pharynx), commonly resulting in a sore throat. It is a frequently encountered condition that prompts individuals to seek medical advice.
Classification
Acute pharyngitis can be categorized based on its underlying cause:
Streptococcal Pharyngitis
Tonsillitis I: Introduction
Etiology
Three primary contributing factors have been identified.
Rheumatic Heart Disease I: Introduction
Rapid Identification of Pathogens
Pneumonia III: Complications and Assessment
