Table 2.
Routine Culture and POC Testing Results by Clinical Status for Patients with Acute Pharyngitis
| Centor Score* | Patients, # | Routine Cultures with GAS, # (%) | POC Tests with GAS, # | Sensitivity of POC Test (95% CI) | Specificity of POC Test (95% CI) | Likelihood Ratio† | |
|---|---|---|---|---|---|---|---|
| Positive | Negative | ||||||
| 0–1 | 55 | 6 (11) | 4 | 67 (22 to 96) | 100 (93 to 100) | 3.0 | 0.8 |
| 2 | 45 | 16 (36) | 15 | 94 (71 to 100) | 100 (88 to 100) | 5.9 | 0.3 |
| 3 | 30 | 10 (33) | 10 | 100 (69 to 100) | 100 (83 to 100) | 4.1 | 0.4 |
| 4 | 18 | 6 (33) | 6 | 100 (59 to 100) | 100 (74 to 100) | 2.2 | 0.6 |
| 3 or 4 | 48 | 16 (33) | 16 | 100 (88 to 100) | 100 (89 to 100) | 8.1 | 0.1 |
| 2–4 | 93 | 32 (34) | 31 | 98 (88 to 100) | 100 (94 to 100) | 15.7 | 0.1 |
| Any | 148 | 38 (26) | 35 | 92 (80 to 98) | 100 (97 to 100) | 24.2 | 0.2 |
*
Clinical status assessed using the Centor score.
†
Calculated to assess the minimum value for likelihood ratio positive using the following calculation: likelihood ratio positive=sensitivity (lower bound of 95% CI)/(1−specificity [lower bound of 95% CI]); likelihood ratio negative=(1−sensitivity [lower bound of 95% CI])/Specificity (lower bound of 95% CI).
GAS, group A β-hemolytic streptococcus; POC, point of care; CI, confidence interval.