Statistics from Altmetric.com
Commentary on the paper by Leroy et al (see page241)
Many children are investigated for vesicoureteric reflux (VUR) following a urinary tract infection (UTI), but the imaging technique of a voiding cystourethrogram (VCUG) is unpleasant for the child and not without risk. A clinical scoring system capable of confidently predicting VUR would therefore be an attractive alternative approach.
The original study by Oostenbrink and colleagues1 seemed to suggest that a score derived from the combination of clinical factors (age, sex, and positive family history), ultrasound findings and C reactive protein (CRP) result could predict the presence of VUR with high sensitivity, albeit with rather low specificity. A diagnostic test with 100% sensitivity can be useful in ruling out a condition when it is negative, even when it has low specificity (that is, cannot be relied upon when positive). This has been referred to as a “SnNout” (when a test has a high Sensitivity, a Negative result rules out the diagnosis).2 However, the lower the specificity, the smaller would be the expected proportion of children without reflux who have a negative result, and thereby avoid an unnecessary imaging investigation. A negative result, excluding VUR, was seen in 17% of children without VUR in Oosterbrink’s series.
Leroy and colleagues3 are to be commended on repeating the work of Oostenbrink. When a group of patients is used to develop a diagnostic test, the performance of that test tends to be overestimated. This is particularly …
Competing interests: none declared
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.