The impact of positive and negative urinary nitrite stick test results (assuming a sensitivity of 0.52 and specificity of 0.99) on the PRU figures of a child having a UTI, according to the prior probability (likely clinical prevalence) of them having a positive diagnosis
| Likely clinical prevalence (%) | 0.1 | 0.5 | 1 | 5 | 10 | 25 | 50 | 75 | 90 | 95 |
|---|---|---|---|---|---|---|---|---|---|---|
| PRU, proportionate reduction in uncertainty; UTI, urinary tract infection. | ||||||||||
| Positive test – PRU | 0.049 | 0.203 | 0.338 | 0.718 | 0.836 | 0.927 | 0.962 | 0.975 | 0.979 | 0.980 |
| Negative test – PRU | 0.515 | 0.514 | 0.513 | 0.502 | 0.489 | 0.444 | 0.347 | 0.210 | 0.096 | 0.050 |