These two authors contributed equally to this study.
Clinical diagnosis of pandemic A(H1N1) 2009 influenza in children with negative rapid influenza diagnostic test by lymphopenia and lower C-reactive protein levels
Article first published online: 7 NOV 2013
© 2013 The Authors. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Influenza and Other Respiratory Viruses
Volume 8, Issue 1, pages 91–98, January 2014
How to Cite
2014) Clinical diagnosis of pandemic A(H1N1) 2009 influenza in children with negative rapid influenza diagnostic test by lymphopenia and lower C-reactive protein levels. Influenza and Other Respiratory Viruses 8(1), 91–98.et al. (
- Issue published online: 20 DEC 2013
- Article first published online: 7 NOV 2013
- Manuscript Accepted: 10 AUG 2013
- Chang Gung Memorial Hospital. Grant Numbers: CMRPG880643, CMRPG8A0731
- National Science Council of Taiwan. Grant Number: NMRP 100-2314-B-182A-051
- diagnostic tests;
- pandemic A (H1N1) 2009 influenza;
- sensitivity and specificity
The sensitivity of rapid influenza diagnostic test (RIDT) of children with influenza-like illness (ILI) remains low.
We compare the parameters between pandemic A(H1N1) 2009 influenza with negative RIDT and ILI not H1N1 for improving the low sensitivity of RIDT for children with ILI.
In a cohort of consecutive laboratory-confirmed H1N1 influenza, we identified 150 H1N1 children with positive RIDT, 152 H1N1 children with negative RIDT, and 75 children with ILI not H1N1. Viral load in throat, complete blood count (CBC), and C-reactive protein (CRP) levels between H1N1 children with negative RIDT and children with ILI not H1N1 were assessed.
The diagnostic sensitivity of the RIDT was 45·5%. An analysis of CBC and CRP levels indicated that H1N1 children with negative RIDT had lower total leukocyte, neutrophil, lymphocyte, and basophil counts, and serum CRP levels (P < 0·01). Lymphocyte counts less than 1500 cells/mm3 and CRP levels <15 mg/l, determined by a receiver operating characteristic curve, showed a diagnostic sensitivity of 52·5% and 80·7%, respectively. Combining the lymphocyte counts and CRP levels provided a diagnostic sensitivity of 91·5%. Moreover, H1N1 children with negative RIDT had a lower viral load than those with positive RIDT (3·33 versus 4·48 log10 copies/ml, P < 0·001); the viral load was negatively correlated to the lymphocyte count (P < 0·001).
A combination of a low lymphocyte count and a low CRP level could, in the early disease phase, provide a useful screening for H1N1 children with false-negative RIDT, potentially facilitating differential diagnoses.