Laboratory markers among children with respiratory tract infection using a multiplex PCR test

Evidence on the comparative impact of laboratory markers on multiple respiratory viruses is scarce. This study aimed to evaluate the comparative impact of multiple respiratory viruses among symptomatic children on laboratory markers, including C-reactive protein (CRP) levels.

This was a retrospective observational study between April 2018 and August 2024 for children aged 15 years or younger who received a blood and multiplex polymerase chain reaction (PCR) tests from a nasopharyngeal swab. Children with fever or respiratory symptoms underwent multiplex PCR, irrespective of symptom severity. A generalized linear regression model was used to evaluate the impact of the variables on each inflammatory marker.

Overall, 3,893 multiplex PCR tests were included in the analysis. Pathogen co-detection was not significant for any laboratory marker (e.g., for CRP: Coefficient 0.03 [95 % confidence interval -0.21, 0.28] and p=0.778). Adenoviruses were positively associated with CRP levels (coefficient 0.28 [0.07, 0.50]; p=0.010). SARS-CoV-2 was negatively associated with CRP level (coefficient -0.56 [0.79, -0.32] and p<0.001). Negative multiplex PCR results were associated with higher CRP levels (coefficient, 0.20 [0.00, 0.40]; p=0.046).

Our study showed a positive association between adenovirus and negative multiplex PCR test results and a negative association between SARS-CoV-2 and CRP levels. Our study may support a better interpretation of laboratory results and the clinical management of children with respiratory tract infection.