Publication:

Evaluating the role of C-reactive protein velocity in identifying viral infections in children with elevated C-reactive protein levels

Background C-reactive protein (CRP) is routinely used to differentiate between bacterial and viral infections in children. However, despite clinical features suggestive of viral illness, several viral infections may present with markedly elevated CRP levels, leading to diagnostic uncertainty and unnecessary antibiotic use. C-reactive protein velocity (CRPv) may improve identification of viral infections in children presenting with elevated CRP levels.

Methods A prospective observational study was conducted among children aged 6 months to 12 years admitted with fever, and CRP >20 mg/l. Viral infection was confirmed using nasopharyngeal viral PCR. Serum CRP was measured at admission and after 24 hours to calculate CRPv. CRPv was compared between viral positive and viral negative groups using appropriate statistical tests.

Results 61 children were enrolled, including 42 (68.9%) with PCR-confirmed viral infections and 19 (31.1%) in viral-negative group. CRP velocity was significantly lower in the viral-positive group (median (Q1–Q3): −0.458 (−1.39 to −0.177) vs. 0.375 (0.0625–0.458) mg/l/hour; p<0.001). ROC analysis demonstrated good performance of CRP velocity, with an AUC of 0.881 (95% CI: 0.786–0.976, p<0.001). A cutoff of ≤−0.125 mg/l/hour yielded a sensitivity of 78.6% and specificity of 94.7%.

Conclusion CRP velocity demonstrated good discriminatory performance in identifying PCR-confirmed viral infections in children with elevated admission CRP level. A greater decline in CRP over the first 24 hours was strongly associated with viral infections, suggesting that serial CRP measurements may serve as a useful marker in early clinical decision-making and help optimize antimicrobial stewardship.