1034. The Positivity of Rapid Influenza Antigen Test Is Not Correlated with Influenza Symptom Severity Score in PCR-Confirmed Patients with Influenza A pandemic (H1N1) 2009
Session: Poster Abstract Session: Diagnostic Procedures in Clinical Practice
Saturday, October 22, 2011
Room: Poster Hall B1
Background: Rapid influenza antigen test (RIDT) might be useful, because they have a fast turnaround time. We investigated the correlation between the positivity of RIDT and the degree of influenza symptom severity.

Methods:During the period from 14 October 2009 to 16 November 2009, real-time reverse transcriptase polymerase chain reaction (rRT-PCR)-confirmed 362 patients with influenza A pandemic (H1N1) aged 8 years and older underwent the rapid antigen test (SD Influenza Antigen, Standard Diagnostics, Yongin, Korea) at same time in the Pandemic Influenza Clinic at Wonju Christian Hospital, Yonsei University Wonju College of Medicine, Wonju, Korea. The presence and severity of influenza symptoms of cough, nasal obstruction, sore throat, fatigue, headache, myalgia, and feverishness on a fourpoint scale (0 absent, 1 mild, 2 moderate, and 3 severe) was recorded by the patients just before RIDT and rRT-PCR. We investigated the determinatives of positivity of RIDT among rRT-PCR-confirmed patients with influenza A pandemic (H1N1) 2009.

Results:  Mean age was 16.7±10.9 year old (range 8-64) and 193 (53.3%) patients were male. The positive rate of RIDT was 64.4% (233 of 362 patients). The mean symptom score was 9.25±4.07. There were no differences in sex, age, duration of symptom, influenza symptom severity score (ISSS). Among rRT-PCR comfirmed patients, linear regression found that only the value of cycle threshold (Ct) of rRT-PCR was correlated with the positivity of RIDT (p<0.001), but ISSS was not correlated with the positivity of RIDT (p=0.804).

Conclusion:  The positivity of RIDT was not correlated with influenza symptom severity score in rRT-PCR-confirmed patients with influenza A pandemic (H1N1). It emphasize that negative result of RIDT can not rule out influenza infection even though patients’ symptom is severe.


Subject Category: J. Clinical practice issues

Young Keun Kim, MD, PHD, Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, South Korea, Hee Kyoung Choi, Yonsei University Wonju College of Medicine, Wonju, South Korea, Hyo Youl Kim, MD, PhD, Division of Infectious Diseases, Yonsei University Wonju College of Medicine, Wonju, South Korea and Young Uh, MD, PhD, Dept. of Laboratory Medicine, Yonsei University Wonju College of Medicine, Wonju, South Korea

Disclosures:

Y. K. Kim, None

H. K. Choi, None

H. Y. Kim, None

Y. Uh, None

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