title: [The application of indirect immuno-fluorescence assay in the diagnosis of severe acute respiratory syndrome].
abstract: OBJECTIVE
  To explore the temporal profile of serum antibody against coronavirus in patients with severe acute respiratory syndrome (SARS), and to evaluate the reliability of indirect immuno-fluorescence assay (IFA) in the diagnosis of SARS.
  
  
  METHODS
  Clinically confirmed SARS patients, suspected SARS patients, and controls were included in the study. IFA was used to detect the serum antibody against SARS coronavirus. General information about the subjects was collected using a standard questionnaire.
  
  
  RESULTS
  The positive rates of specific IgG and IgM against SARS virus within 10 days after onset of the disease were 55.1% and 16.3% respectively and then increased up to 89.8% for IgG and 65.3% for IgM. After 25 days of the onset of the disease, 90.9% patients became positive for both IgG and IgM. Results from chi-square for trend test revealed that the positive rates of both IgG and IgM increased with time (chi(2) for trend = 16.376, P = 0.00005 for IgG; chi(2) for trend = 28.736, P = 0.00000 for IgM). Sensitivity, specificity and agreement value of IFA regarding the diagnosis of SARS were all higher than 90%.
  
  
  CONCLUSIONS
  IFA can be used to assist diagnosis of SARS after 10 days of the onset of disease.
authors.affiliation: Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Li-qun
authors.initials: LQ
authors.lastname: Fang
authors.forename: Pan-he
authors.initials: PH
authors.lastname: Zhang
authors.forename: Bao-an
authors.initials: BA
authors.lastname: Yang
authors.forename: Xiao-ming
authors.initials: XM
authors.lastname: Wu
authors.forename: Qiu-min
authors.initials: QM
authors.lastname: Zhao
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Yong-qiang
authors.initials: YQ
authors.lastname: Deng
authors.forename: Lin
authors.initials: L
authors.lastname: Zhan
authors.forename: Wei-guo
authors.initials: WG
authors.lastname: Han
authors.forename: Fu-shuang
authors.initials: FS
authors.lastname: Lu
authors.forename: Jin-song
authors.initials: JS
authors.lastname: Wu
authors.forename: Hong
authors.initials: H
authors.lastname: Yang
authors.forename: Qing-yu
authors.initials: QY
authors.lastname: Zhu
authors.forename: Wu-chun
authors.initials: WC
authors.lastname: Cao
mesh_terms: D000914:Antibodies, Viral / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology*; D045169:Severe Acute Respiratory Syndrome / Q000175:diagnosis*
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G; D007075:Immunoglobulin M