I. Indications

Evaluation for Group A Streptococcal Pharyngitis

II. Criteria: Modified Centor (recommended)

Tonsillar exudate or erythema
Anterior cervical adenopathy
Cough absent
Fever present
Age
Age 3 to 14 years: +1 point
Age 15 to 45 years: 0 points
Age over 45 years: -1 points

III. Approach: Clinical Suspicion based on scoring above

Strep Score 4 to 5 (or Strep Score 2 if patient unreliable)
Treat with antibiotics
Strep Score 2 to 3: Perform rapid antigen test
Antigen test positive: Treat with antibiotics
Antigen test negative: Throat Culture
Strep Score 0 to 1
Provide Pharyngitis Symptomatic Treatment

V. Interpretation (Clinic and ER probability based on original criteria)

Based on original criteria above
Score 0: Streptococcus probability 1% (3% in ER)
Score 1: Streptococcus probability 4% (8% in ER)
Score 2: Streptococcus probability 9% (18% in ER)
Score 3: Streptococcus probability 21% (38% in ER)
Score 4: Streptococcus probability 43% (63% in ER)

http://www.fpnotebook.com/ent/exam/StrpScr.htm