Algorithm of Hoffmann for Use of Throat Swabs in Patients with Acute Pharyngo-Tonsillitis

 

Population: 2,225 outpatients seen by general practitioners in Denmark over a 1 year period (includes both children and adults). The prevalence of group A streptococcal isolates in population studied was 25%.

 

Signs:

(1) enlarged or hyperemic tonsils

(2) exudate

(3) enlarged or tender angular lymph nodes

(4) fever >= 38°C

Pain on Swallowing	Number of Signs Present	Cough and Coryza	Group
absent	NA	NA	1
present	0	NA	2
present	1 or 2	both present	3
present	1 or 2	one or neither	4
present	3 or 4	NA	5

 

where:

• Several of the parameters overlap with the criteria of Centor et al.

 

Throat swabs for Group A streptococcus is performed in patients with a probability of Group A streptococcal infection moderately higher than the overall prevalence:

(1) in all patients <= 14 years of age

(2) patients 15 – 44 years of age in Groups 4 and 5

(3) patients >= 45 years of age in Group 5

 

Patients with a low probability for Group A streptococcal infection did not have their throat swabbed and were not treated with antibiotics.

 

Performance of algorithm:

• The sensitivity was 95% and specificity 26%.

• 80% of patients had swabs taken.

• The positive predictive value was 36% and negative predictive value 92%.