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Strep Score

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Strep Score, Walsh Pharyngitis Criteria, McIsaac Decision Rule, Modified Centor Criteria

  • See Also
  1. Streptococcal Pharyngitis
  2. FeverPAIN Streptococcal Pharyngitis Score
  • Indications
  1. Group A Streptococcal Pharyngitis Diagnosis
  • Criteria
  • Modified Centor Criteria (McIsaac Scoring, recommended)
  1. Centor Criteria (one point for each of 4 criteria)
    1. Tonsillar exudate or erythema
    2. Swollen, tender anterior cervical adenopathy
    3. Cough absent
    4. Fever present (>100.4 F or >38 C)
  2. Age (modifier added in McIsaac Criteria)
    1. Age 3 to 14 years: +1 point
    2. Age 15 to 45 years: 0 points
    3. Age over 45 years: -1 points
  3. Interpretation (McIsaac = Centor + Age Modifier)
    1. Strep Score 4 to 5 (or Strep Score 2 if patient unreliable)
      1. Treat with Antibiotics
    2. Strep Score 2 to 3: Perform rapid Antigen test
      1. Antigen test positive: Treat with Antibiotics
      2. Antigen test negative: Throat Culture (not needed if strep testing via PCR)
    3. Strep Score 0 to 1
      1. Provide Pharyngitis Symptomatic Treatment
  • Criteria
  • Older, original criteria with derivation (1 point for each clinical finding)
  1. Original Criteria (interpretation below based on these)
    1. Tonsillar exudate
    2. Tender, anterior cervical adenopathy
    3. Cough absent
    4. Fever present
  2. Modifiers (Not included in interpretation below)
    1. McIsaac Decision Rule modifier
      1. Age younger than 15 years: +1 point
      2. Age 15 to 45 years: 0 points
      3. Age over 45 years: -1 points
      4. McIsaac (2000) CMAJ 163:811-5 [PubMed]
    2. Exposure to known Pharyngitis contact
      1. Added with Walsh Clinical Prediction Rules
      2. McGinn (2003) Mayo Clin Proc 78:289-93 [PubMed]
  3. Interpretation (Original Centor criteria without modifiers (clinic and ER probability)
    1. Based on original criteria above
    2. Score 0: Streptococcus probability 1% (3% in ER)
    3. Score 1: Streptococcus probability 4% (8% in ER)
    4. Score 2: Streptococcus probability 9% (18% in ER)
    5. Score 3: Streptococcus probability 21% (38% in ER)
    6. Score 4: Streptococcus probability 43% (63% in ER)
  4. References
    1. Centor (1990) in Sox (1990) Common Diagnostic, p.247
  • References
  1. Centor (1990) in Sox (1990) Common Diagnostic, p.247
  2. Sloane (1998) Family Medicine, p. 629