The Importance of Fast Strep Throat Diagnosis We've all experienced the discomfort of a sore throat, but when the pain becomes severe and is accompanied by fever or swollen glands, it may be a sign of strep throat. Strep throat is caused by a bacterial infection caused by group A Streptococcus (GAS), and unlike viral sore throats, it requires antibiotic treatment to avoid complications. The good news? Diagnosing strep throat is quick and easy ...