Anal. 15 min after the sample is applied. RICT with several pairs of MoAbs showed a high sensitivity for the detection of recombinant N\Ag as well as viral N\Ag of SARS\CoV. rSN122 and rSN21\2 were the best MoAbs for immobilized antibody and enzyme labeling, respectively. With regard to analytical sensitivity, RICT detected N\Ag at 31 pg/mL for recombinant N\Ag, and at 1.99102 TCID50/mL for SARS\CoV. The specificity of RICT was 100% when 150 human sera and 50 nasopharyngeal aspirates (NSPs) were used. RICT based on an EIA using the rSN122/rSN21\2 pair is a sensitive, specific, and reliable rapid assay for detecting N\Ag in SARS\CoV treated with either heat or Triton X\100. J. Clin. Lab. Anal. 19:150C159, 2005. ? 2005 Wiley\Liss, Inc. strong class=”kwd-title” Keywords: rapid immunochromatographic test (RICT), severe acute respiratory syndrome\associated coronavirus (SARS\CoV), nucleocapsid antigen (N\Ag) ?AbbreviationsSARSsevere acute respiratory syndromeSARS\CoVSARS\associated coronavirusRICTrapid immunochromatographic testEIAenzyme immunoassayN\Agnucleocapsid antigenMoAbmonoclonal antibodyTCID5050 tissue culture infective dose virusWBWestern blottingSDS\PAGEsodium dodecyl sulfate\polyacrylamide gel electrophoresisPODperoxidaseBSAbovine serum albuminALPalkaline phosphataseNP\40Nonidet\P40 REFERENCES 1. Peiris JSM, Lai ST, Poon LLM, et al. Coronavirus as a possible cause of severe acute respiratory syndrome. Lancet 2003;361:1319C1325. [PMC free article] [PubMed] [Google Scholar] 2. Ksiazek TG, Erdman D, Goldsmith CS, et al. A novel coronavirus associated with severe acute respiratory syndrome. N Engl J Med 2003;348:1953C1966. [PubMed] [Google Scholar] 3. Rota RA, Oberste MS, Monroe SS, et al. Characterization of a novel coronavirus associated with severe acute respiratory syndrome. Science 2003;300:1394C1399. [PubMed] [Google Scholar] 4. Marra MA, Jones SJM, Astell CR, et al. The genome sequence of the SARS\associated coronavirus. Science 2003;300:1399C1404. [PubMed] [Google Scholar] 5. Ng DFNB39 EK, Hui DS, Chan KC, et al. Quantitative analysis and prognostic implication of SARS coronavirus RNA in the plasma and serum of patients with severe acute respiratory syndrome. Clin Chem 2003;49:1976C1980. [PMC free article] [PubMed] [Google Scholar] 6. Poon LLM, Wong OK, Luk W, Yuen KY, Peiris JS, Guan Y. Rapid diagnosis of a coronavirus associated with severe acute respiratory syndrome (SARS). Clin Chem 2003;49:953C955. [PMC free article] [PubMed] [Google Scholar] 7. Che XY, Qiu LW, Pan YX, et al. Sensitive and specific monoclonal antibody\based capture enzyme immunoassay for detection of nucleocapsid antigen in sera from patients with severe acute respiratory syndrome. J Clin Microbiol 2004;42:2629C2635. [PMC free article] [PubMed] [Google Scholar] 8. Shi Y, Yi Y, Li P, et al. Diagnosis of severe acute respiratory syndrome (SARS) (-)-Epicatechin gallate by detection of SARS coronavirus nucleocapsid antibodies in an antigen\capturing enzyme\linked immunosorbent assay. J Clin Microbiol 2003;41:5781C5782. [PMC free article] [PubMed] [Google Scholar] 9. Huang LR, Chiu CM, Yeh SH, et al. Evaluation of antibody responses against SARS coronaviral nucleocapsid or spike proteins by immunoblotting or ELISA. J Med Virol 2004;73:338C346. [PMC (-)-Epicatechin gallate free article] [PubMed] [Google Scholar] 10. Kasahara Y, Ashihara Y. Simple devices and their possible application in clinical laboratory downsizing. Clin Chim Acta 1997;267:87C102. [PubMed] [Google Scholar] 11. Guan M, Chen HY, Foo SY, Tan YJ, Goh PY, Wee SH. 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 Diagnost Lab Immunol 2004;11:287C291. [PMC free article] [PubMed] [Google Scholar] 12. Wu HS, Chiu SC, Tseng TC, et al. Serologic and molecular biologic methods for SARS\associated coronavirus infection, Taiwan. Emerg Infect Dis 2004;10:304C310. [PMC free article] [PubMed] [Google Scholar] 13. Kohler G, Milestein C. Continuous cultures of fused cells secreting antibodies of predefined specificity. Nature 1975;256:495C497. [PubMed] [Google Scholar] 14. Nishizono I, Iida S, Suzuki N, et al. Rapid and sensitive chemiluminescent enzyme immunoassay for measuring tumor markers. Clin Chem 1991;37:1639C1644. [PubMed] [Google Scholar] 15. Fujimura K, Ise N, Ueno E, Hori T, Fujii N, Okada M. Reactivity of recombinant treponema pallidum(r\Tp) antigens with anti\Tp antibodies in human syphilitic sera evaluated by ELISA. J Clin Lab Anal 1997;11:315C322. [PMC free article] [PubMed] [Google Scholar] 16. Frohman MA, Dush MK, Martin GR. Rapid production of full\length cDNAs from rare transcripts; amplification using a single gene\specific oligonucleotide (-)-Epicatechin gallate primer. Proc Natl Acad Sci USA 1988;85:8998C9002. [PMC free article] [PubMed] [Google Scholar] 17. Escors D, Ortego J, Laude H, Enjuanes L. The membrane M protein carboxy terminus binds to transmissible gastroenteritis coronavirus core and contributes to core stability. J Virol 2001;75:1312C1324. [PMC free article] [PubMed] [Google Scholar] 18. NCBI . http://www.ncbi.nlm.nih.gov/;P59595, nucleocapsid protein (N structural protein) (NC)..