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C-reactive protein level insufficient diagnostic marker for febrile children

In general practice out-of-hours service, C-reactive protein level has little clinical value in distinguishing febrile children in need of medical care from those who are not, according to recent study findings.

“Although [C-reactive protein (CRP)] concentration is often routinely measured in pediatric departments, testing for CRP has little influence on decision making,” Marijke Kool, GP, PhD, from the department of general practice at Erasmus Medical Center, in Rotterdam, the Netherlands, and colleagues wrote. “From that perspective, and based on a systematic review, it was suggested that different cutoff levels could be used to rule in or rule out [serious infection] in febrile children; however, no study in the latter review was performed in a low-prevalence general practice setting.”

The researchers evaluated whether CRP levels in young children with fever presenting to a general practice out-of-hours service could predict an increased risk for serious infection at presentation or during 1-week follow-up.

This prospective cohort study included 440 children aged three months to six years, presenting with fever to a general practitioner out-of-hours service in the southern part of Rotterdam. For their index test, Kool and colleagues used CRP levels 20 mg/L or lower to rule out a serious infection and levels higher than 80 mg/L to rule in a serious infection. Referral to a pediatric ED or diagnosis of a serious infection was used as the reference standard. The main outcome measure was CRP value.

They found CRP levels of 20 mg/L or less did not alter the chance of not having a serious infection (87.5%) and CRP levels higher than 80 mg/L increased the likelihood of having a serious infection from 11.4% (pretest) to 21.2% (posttest). CRP could not predict a serious infection during follow-up in patients without diagnosis at presentation (CRP > 80 mg/L: positive likelihood ratio, 2.1, 95% CI, 1.3–3.5; CRP ≤ 20 mg/L: negative likelihood ratio, 0.9, 95% CI, 0.7–1.2).

“These findings lead us to conclude that CRP has little clinically relevant value in the triage of febrile children, that is, in discriminating those in need of medical care from those who are not,” Kool and colleague wrote. “However, the additional value of CRP in the management of febrile children needs further evaluation in randomized clinical trials.” – by Savannah Demko

Disclosure: The researchers report no relevant financial disclosures.