gms | German Medical Science

International Conference on SARS - one year after the (first) outbreak

08. - 11.05.2004, Lübeck

Test systems for the detection of coronavirus causing severe acute respiratory syndrome (SARS-CoV)


  • corresponding author presenting/speaker Karen Sonnenberg - EUROIMMUN AG, Lübeck, Germany
  • Holger Hennig - University of Lübeck, Institute of Immunology and Transfusion Medicine, Lübeck, Germany
  • Huiping Yan - Faculty of Infectious Diseases, You An Hospital, Capital Medical University, Beijing, China
  • Zhongping He - Ditan Hospital, Beijing, China
  • Matthias Niedrig - Robert-Koch-Institute, Berlin, Germany
  • Thomas Pfeiffer - EUROIMMUN AG, Lübeck, Germany
  • Katja Steinhagen - EUROIMMUN AG, Lübeck, Germany
  • Britta Arp - EUROIMMUN AG, Lübeck, Germany
  • Wolfgang Schlumberger - EUROIMMUN AG, Lübeck, Germany
  • Winfried Stöcker - EUROIMMUN AG, Lübeck, Germany

International Conference on SARS - one year after the (first) outbreak. Lübeck, 08.-11.05.2004. Düsseldorf, Köln: German Medical Science; 2004. Doc04sars8.03

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Veröffentlicht: 26. Mai 2004

© 2004 Sonnenberg et al.
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Introduction: SARS-CoV is the infectious agent responsible for the epidemic outbreak of SARS. We have developed and evaluated three test methods for identifying infections with SARS-CoV.

Materials and Methods: Sera from 34 patients with clinically defined SARS were investigated by real time RT-PCR, indirect immunofluorescence test (IIFT) and ELISA. The samples were taken 1-52 days after onset of symptoms. Sera from 200 blood donors were also analysed. (a) For virus detection, RNA was extracted from patient serum samples and converted into DNA, amplified and directly detected by real time RT-PCR (TaqMan assay). (b) Anti-SARS-CoV antibodies class IgG and IgM were analysed by IIFT using microscope slides with two BIOCHIPs in each field - one coated with SARS-CoV-infected cells and the other with non-infected cells. Incubation was carried out under standardized conditions (TITERPLANE technique, EUROIMMUN). (c) Anti-SARS-CoV antibodies class IgG were also tested using ELISA: microplate wells were coated with a native SARS-CoV extract. Bound human antibodies in IIFT and ELISA were visualized using FITC- or peroxidase-labelled anti-human IgG/IgM, respectively. In a second study, only performed with IIFT, 530 SARS patient samples were investigated for anti-SARS-CoV antibodies class IgG and IgM.

Results: All of the 34 SARS patient sera (100%) were positive in either the nucleic acid based assay or the antibody test systems. In the early stage of infection (day 1-9 after onset of symptoms, 12 patients) IgG-antibodies were found in only 2 of the samples, whereas all of them were positive in the RT-PCR assay. Of 22 patients showing symptoms for more than 9 days, 10 were positive in PCR, while 21 were antibody positive with a 100% correlation between ELISA and IIFT. Sera from 200 blood donors were found to be negative in all assays. The samples of the second study were divided into 3 groups (depending on the days after onset of symptoms) as shown in the table below. [Tab. 1]

The prevalence of class IgG antibodies was higher than the prevalence of class IgM antibodies in patient samples of every stage of infection, even in the acute phase.

Discussion: PCR predominantly allows the identification of fresh infections. In later stages of illness (≥10 days after onset of symptoms) antibody determination using IIFT or ELISA are the most reliable methods for identifying current or past infections with SARS-CoV.

Conclusion: To exclude or verify a SARS-CoV-infection it seems to be sufficient to analyse serum as the only source and perform both tests - a real time RT-PCR for direct diagnosis of the virus and an antibody test using IIFT or ELISA.