Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Drescher, M.
Development of a clinical score for diagnosis of Influenza A/ H1N1 infection and differentiation from influenza- like illnesses
Comparison of laboratory values between PCR confirmed H1N1 influenza and PCR negative influenza-like illnesses
[ Diplomarbeit ] Medical University of Graz; 2013. pp. 80
[OPEN ACCESS]
FullText
- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Hönigl Martin
- Krause Robert
- Altmetrics:
- Abstract:
- Aim During the 2009 influenza A /H1N1 pandemic more than 18000 people lost their lives worldwide. Reliable and rapid diagnosis is essential to initiate appropriate antiviral therapy in influenza as treatment is most effective when initiated within 48 to 72 hours after the onset of symptoms. PCR is the gold standard to confirm H1N1 but is expensive and results usually are not available in time for therapeutic or preventive decisions within 72h after onset of symptoms. The currently available antigen tests are fast but display low sensitivity. The development of a clinical score for H1N1 influenza may facilitate the decision whether or not to initiate antiviral treatment, improve outcome and reduce morbidity and mortality. As a possible component of a proposed score in the future we retrospectively analyzed the differences in laboratory values between patients with PCR confirmed H1N1 influenza and patients with clinical suspicion but negative PCR for influenza (=influenza-like illness [ILI]). Methods During Oct 2009 and Jan 2010 H1N1 PCR was performed in 1681 patients with clinical suspicion of influenza. 624 patients had a positive and 1057 patients had a negative H1N1 PCR result. Laboratory data sets were available from 221/624 (35%) H1N1 patients and 312/1057 (30%) ILI patients. Differences in laboratory values between both groups and correlation of laboratory values with underlying disease were calculated using the Mann-Whitney U test , and p<0.05 was considered significant. Results At initial presentation the median of the total white blood cell count (WBC) in the H1N1 influenza group was 6.7 G/l (IQR, 5- 8.6 G/l) and therefore significantly lower than in the ILI group (median 9.86 G/l [IQR, 7.35- 13.74 G/l]); p < 0.001). A similar pattern was seen for day 3 and 5 values of leukocytes during hospitalization. Also thrombocyte count at admission was significantly lower in patients with PCR confirmed H1N1 infection than in patients with ILI (201 G/l [IQR, 156.5- 225 G/l] versus 232 G/l [IQR, 182- 288.5 G/l]; p < 0.001). In the distribution of the WBC count only the relative eosinophil count showed significantly lower values in patients with confirmed H1N1 infection (p= 0.006). Comparison of C- reactive protein (CRP) values between PCR confirmed H1N1 influenza and PCR negative ILI demonstrated that CRP was significantly lower in patients with H1N1 (11 mg/l [IQR, 5- 64 mg/l] versus 23 mg/l [IQR, 7- 100.85 mg/l]; p < 0.001). Furthermore, also gamma-Glutamyl-Transferase (GGT) was significantly lower in patients with confirmed H1N1 infection (p< 0.05). Creatine kinase (CK) values were significantly higher in patients with PCR confirmed H1N1 infection (113 U/l [IQR, 61.5- 192 U/l] versus 72 U/l [IQR, 48.5- 116.5 U/l]; p< 0.001). Conclusion The results revealed that there were significant differences in laboratory admission values between people with PCR confirmed H1N1 influenza and those with PCR negative influenza-like illnesses. Total white blood cell count, relative and absolute eosinophil count, thrombocytes, CRP and GGT were significantly lower in patients with confirmed H1N1 infection, while creatine kinase values were significantly higher. The results of this study might contribute to the implementation of a clinical score for a more efficient and faster clinical diagnosis of a H1N1 infection.