Recombinant protein-based enzyme-linked immunosorbent assay and immunochromatographic tests for detection of immunoglobulin G antibodies to severe acute respiratory syndrome (SARS) coronavirus in SARS patients

Clin Diagn Lab Immunol. 2004 Mar;11(2):287-91. doi: 10.1128/cdli.11.2.287-291.2004.


An enzyme-linked immunosorbent assay (ELISA) and a rapid immunochromatographic test for detection of immunoglobulin G (IgG) antibodies in severe acute respiratory syndrome (SARS) patients were developed by utilizing the well-characterized recombinant proteins Gst-N and Gst-U274. The ELISA detected IgG antibodies to SARS-CoV in all 74 convalescent-phase samples from SARS patients while weakly cross-reacting to only 1 of the 210 control sera from healthy donors. This finding thus led to a kit sensitivity, specificity, and accuracy of 100, 99.5, and 99.6%, respectively. The test thus provided a positive predictive value (PPV) of 98.7% and a negative predictive value (NPV) of 100%. In addition, the ELISA gave a positive delta of 5.4 and a negative delta of 3.6, indicating an excellent differentiation between positives and negatives. The same recombinant proteins were also applied to a newly developed platform for the development of a 15-min rapid test. The resulting rapid test has an excellent agreement of 99.6%, with a kappa value of 1.00, with the ELISA. Again, this rapid test was able to detect 100% of the samples tested (n = 42) while maintaining a specificity of 99.0% (n = 210). The PPV and NPV for the rapid test thus reached 95.3 and 100%, respectively.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Viral / analysis
  • Antibodies, Viral / immunology
  • Enzyme-Linked Immunosorbent Assay / methods*
  • Humans
  • Immunoglobulin G / analysis
  • Immunoglobulin G / immunology
  • Predictive Value of Tests
  • Recombinant Proteins / immunology
  • SARS Virus / immunology*
  • SARS Virus / isolation & purification*
  • Sensitivity and Specificity
  • Severe Acute Respiratory Syndrome / diagnosis*
  • Severe Acute Respiratory Syndrome / immunology*


  • Antibodies, Viral
  • Immunoglobulin G
  • Recombinant Proteins