Journal List > Korean J Clin Microbiol > v.13(3) > 1038188

Korean J Clin Microbiol. 2010 Sep;13(3):109-113. Korean.
Published online September 30, 2010.
Copyright © 2010 The Korean Society of Clinical Microbiology
Comparison of Rapid Antigen Test and Real-Time Reverse Transcriptase PCR for Diagnosing Novel Swine Influenza A (H1N1)
Aerin Kwon, Jae-Seok Kim, Han-Sung Kim, Wonkeun Song, Ji-Young Park, Hyoun Chan Cho and Kyu Man Lee
Department of Laboratory Medicine, Hallym University College of Medicine, Seoul, Korea.

Correspondence: Jae-Seok Kim, Department of Laboratory Medicine, Hallym University College of Medicine, Kangdong Sacred Heart Hospital, 445 Gil-dong, Gangdong-gu, Seoul 134-701, Korea. (Tel) 82-2-2224-2327, (Fax) 82-2-2224-2214, Email:
Received January 07, 2010; Revised July 06, 2010; Accepted July 20, 2010.



Novel swine influenza (H1N1) was first identified in Mexico in April 2009. Because of its high infectivity and worldwide distribution, a rapid and efficient screening test is necessary. Here we evaluated the usefulness of a rapid antigen test currently in use, compared to real-time RT-PCR (rRT-PCR) as a screening test for detection of novel swine influenza (H1N1).


A total of 1,228 patients who visited Hallym University Kangdong Sacred Heart Hospital with influenza-like illness between 14 August 2009 and 30 September 2009, and were tested by both rapid antigen and rRT-PCR tests, were enrolled in this study.


Sensitivity, specificity, predictive value of a positive test, and predictive value of a negative test for the rapid antigen test were 30.5%, 99.2%, 86.4% and 90.1%, respectively. Fifty-one (4.2%) patients were positive for both rapid antigen test and rRT-PCR, and 1,053 (85.7%) were negative for both rapid antigen test and rRT-PCR. A total of 124 (10.1%) patients showed a discrepancy between the two tests. Among them, 116 (9.4%) were only positive for rRT-PCR and 8 (0.7%) were only positive for the rapid antigen test. The latter 8 patients all showed negative H1/M2 results in rRT-PCR. There were significant differences in detection rates of the rapid antigen test between different H1 Ct (threshold cycle) interval groups and for different age groups (P<0.05).


Although the rapid antigen test is easy to perform and provides fast results, its limits as a screening test for detection of novel swine influenza (H1N1) due to its low sensitivity compared to rRT-PCR need to be considered in practical situations.

Keywords: Novel swine influenza; H1N1; Rapid antigen test; Real-time PCR; Sensitivity


Fig. 1
Comparison of rapid antigen test sensitivity between different H1 Ct* interval groups among novel swine influenza A (H1N1) patients confirmed by real-time RT-PCR. *Ct, threshold cycle.
Click for larger image


Table 1
Comparison of rapid antigen test and real-time RT-PCR for detection of novel swine influenza A (H1N1)
Click for larger image

Table 2
Comparison of rapid antigen test results between different age groups among novel swine influenza A (H1N1) patients confirmed by real-time RT-PCR
Click for larger image

1. Kim SH, Huh JH, Bae SY, Kim JS, Yoon SY, Lim CS, et al. Epidemiology of respiratory viral infection in 2004-2006. Korean J Lab Med 2006;26:351–357.
2. Lee WG, Lee HK, Kim HJ, Chung JK, Lee EH, Moon HR. Evaluation of a rapid antigen test for detection of influenza virus. Korean J Clin Microbiol 2004;7:119–123.
3. Petric M, Comanor L, Petti CA. Role of the laboratory in diagnosis of influenza during seasonal epidemics and potential pandemics. J Infect Dis 2006;194 Suppl 2:S98–S110.
4. Peiris JS, Poon LL, Guan Y. Emergence of a novel swine-origin influenza A virus (S-OIV) H1N1 virus in humans. J Clin Virol 2009;45:169–173.
5. Gatherer D. The 2009 H1N1 influenza outbreak in its historical context. J Clin Virol 2009;45:174–178.
6. WHO web sites on disease outbreak news. Pandemic (H1N1) 2009 - update 71. World Health Organization. [last visited on 17 October 2009].
7. Panning M, Eickmann M, Landt O, Monazahian M, Olschläger S, Baumgarte S, et al. Detection of influenza A(H1N1)v virus by real-time RT-PCR. Euro Surveill 2009;14:pii: 19329.
8. Vasoo S, Stevens J, Singh K. Rapid antigen tests for diagnosis of pandemic (Swine) influenza A/H1N1. Clin Infect Dis 2009;49:1090–1093.
9. Rahman M, Vandermause MF, Kieke BA, Belongia EA. Performance of Binax NOW Flu A and B and direct fluorescent assay in comparison with a composite of viral culture or reverse transcription polymerase chain reaction for detection of influenza infection during the 2006 to 2007 season. Diagn Microbiol Infect Dis 2008;62:162–166.
10. Song SH. Rapid diagnosis of respiratory virus infection. J Lab Med Qual Assur 2007;29:207–210.
11. Kim JS, Choi HJ, Ahn YM, Hwang YO. Clinical usefulness of rapid antigen test on the diagnosis of influenza. Korean J Pediatr 2005;48:1348–1353.
12. Chan KH, Lai ST, Poon LL, Guan Y, Yuen KY, Peiris JS. Analytical sensitivity of rapid influenza antigen detection tests for swine-origin influenza virus (H1N1). J Clin Virol 2009;45:205–207.
13. Cheng CK, Cowling BJ, Chan KH, Fang VJ, Seto WH, Yung R, et al. Factors affecting QuickVue Influenza A+B rapid test performance in the community setting. Diagn Microbiol Infect Dis 2009;65:35–41.
14. Ruest A, Michaud S, Deslandes S, Frost EH. Comparison of the Directigen flu A+B test, the QuickVue influenza test, and clinical case definition to viral culture and reverse transcription-PCR for rapid diagnosis of influenza virus infection. J Clin Microbiol 2003;41:3487–3493.
15. Centers for Disease Control and Prevention (CDC). Evaluation of rapid influenza diagnostic tests for detection of novel influenza A (H1N1) Virus - United States, 2009. MMWR Morb Mortal Wkly Rep 2009;58:826–829.
16. Kang JO, Kim EC, Lee KM, Lee NY, Lee CK. Surveillance for respiratory virus testing situation in Korea and epidemiology for the respiratory viruses detected in 5 university hospitals: report from virus study group. Korean J Clin Microbiol 2007;10:102–108.
17. Chan KH, Lam SY, Puthavathana P, Nguyen TD, Long HT, Pang CM, et al. Comparative analytical sensitivities of six rapid influenza A antigen detection test kits for detection of influenza A subtypes H1N1, H3N2 and H5N1. J Clin Virol 2007;38:169–171.
18. Yoo Y, Sohn JW, Park DW, Kim JY, Shin HK, Lee Y, et al. Clinical evaluation of the SD Bioline influenza virus antigen test for rapid detection of influenza viruses A and B in children and adults during the influenza season. Clin Vaccine Immunol 2007;14:1050–1052.
19. Mai LQ, Hien PT, Hang NL, Oh JS, Ha GW, Kwon JA, et al. Evaluation of two lateral-flow chromatographic membrane lmmunoassays for rapid detection of influenza virus in limited respiratory specimens. J Lab Med Qual Assur 2005;27:243–249.
20. Chan KH, Maldeis N, Pope W, Yup A, Ozinskas A, Gill J, et al. Evaluation of the directigen FluA+B test for rapid diagnosis of influenza virus type A and B infections. J Clin Microbiol 2002;40:1675–1680.
21. WHO recommendations on the use of rapid testing for influenza diagnosis. World Health Organization. [last visited on July 2005].
22. Steininger C, Kundi M, Aberle SW, Aberle JH, Popow-Kraupp T. Effectiveness of reverse transcription-PCR, virus isolation, and enzyme-linked immunosorbent assay for diagnosis of influenza A virus infection in different age groups. J Clin Microbiol 2002;40:2051–2056.
23. Ginocchio CC, Zhang F, Manji R, Arora S, Bornfreund M, Falk L, et al. Evaluation of multiple test methods for the detection of the novel 2009 influenza A (H1N1) during the New York City outbreak. J Clin Virol 2009;45:191–195.