Cochrane: In
some children with urinary tract infection (UTI), the infection is
localized to the bladder (lower urinary tract). In others, bacteria
ascend from the bladder to the kidney (upper urinary tract). Only
children with upper urinary tract involvement are at risk for developing
permanent kidney damage. If non-invasive biomarkers could accurately
differentiate children with lower urinary tract disease from children
with upper urinary tract disease, treatment and follow-up could
potentially be individualized. Accordingly, we examined the usefulness
of three widely available blood tests (procalcitonin, C-reactive
protein, erythrocyte sedimentation rate) in differentiating upper from
lower urinary tract disease.
We found 24 relevant studies of which 17
provided data for our primary outcome. Six studies (434 children)
provided data for the procalcitonin test; 13 studies (1638 children)
provided data for the C-reactive protein test, and six studies (1737
children) provided data for the erythrocyte sedimentation rate test. We
found all three tests to be sensitive (summary sensitivity values ranged
from 86% to 95%), but not very specific (summary specificity values
ranged from 38% to 71%). None of the tests were accurate enough to allow
clinicians to confidently differentiate upper from lower urinary tract
disease.