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NS1 detection in addition to new dengue antibody assay with differential detection of IgG and IgM antibodies
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Clinical Biochemistry 43 (2010) 537
Letter to the Editor NS1 detection in addition to new dengue antibody assay with differential detection of IgG and IgM antibodies To the Editor We comment on the reported comprehensive utility of unique antibody assay for differential detection of dengue IgG and IgM antibodies [1] that should be improved significantly through concurrent assay for dengue NS1 antigen: dengue NS1 has had a diagnostic performance matching RT–PCR for dengue virus RNA. For example, dengue virus NS1 antigen detection in travelers upon arrival at airports in Taiwan was instrumental towards detection of 19 RT–PCR-negative travelers who would have been labeled dengue-negatives. Two of them turned out to be IgM-positive on days 17 or 18 of illness [2]. Furthermore, in Malaysia, 42 of 55 patients with an acute diagnosis of dengue were positive only for NS1 but were negative for both RT–PCR and viral isolation [3]. During the 2008 spurt in dengue cases in Delhi, a pilot study was made at the Sant Parmanand Hospital to establish utility or otherwise of dengue immunochromatographic kit for detection of NS1 antigen. Employing the dengue NS1 Ag strip (Bio-Rad, Marne-la-coquette), 22 samples from patients with suspected dengue were evaluated. Five patients were positive for NS1 antigen but were negative for dengue IgM and IgG. They were tested negative for dengue RT-PCR, details elsewhere [4], at the National Institute of Communicable Diseases, Delhi. The combined ImmunoComb Dengue IgG& IgM BiSpot kit only when converted into a tri-spot on-line spot assay kit would be ideal for a comprehensive and complete assessment and appreciation of dengue clinical status. Absence of positive control to monitor the working of the obtainable dengue NS1
Ag strip kits (Bio-Rad, Marne-la-coquette) has been rather awkward. A known positive control should be included in every commercial immunochromatographic (lateral flow) test strip kit including the future organics (Yavne, Israel) integrated NS1, IgG, and IgM assay format. Acknowledgment The technical assistance of Ms Beena Michael is acknowledged. References [1] Rivetz B, Siman-Tov, Ambal E, et al. New dengue antibody assay with unique differential detection of IgG and IgM antibodies. Clin Biochem 2009;42:180–4. [2] Shu PY, Yang CF, Kao JF, Su CL, Chang SF, Lin CC, et al. Application of dengue NS1 antigen rapid test for on-site detection of imported dengue cases at airports. Clin Vaccine Immunol 2009;16:589–91. [3] Zaniah S, Wahab AH, Mariam M, Fauziah MK, Khairul AH, Rosalina I, et al. Performance of a commercial rapid dengue NS1 antigen immunochromatography test with reference to dengue NS1 antigen-capture ELISA. J Virol Methods 2009;155:157–60. [4] Kumar M, Pasha ST, Mittal V, Rawat DS, Arya SC, Agarwal N, et al. Unusual emergence of Guate 98-like molecular serotype of DEN-3 during 2003 dengue outbreak in Delhi. Dengue Bull 2004;28:161–7.
Subhash C. Arya* Nirmala Agarwal Sant Parmanand Hospital, 18 Alipore Road, Delhi 110054, India E-mail address: [email protected] (S.C. Arya) *Corresponding author.
0009-9120/$ - see front matter © 2009 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.clinbiochem.2009.08.008
24 April 2009
Clinical Biochemistry 43 (2010) 537
Letter to the Editor NS1 detection in addition to new dengue antibody assay with differential detection of IgG and IgM antibodies To the Editor We comment on the reported comprehensive utility of unique antibody assay for differential detection of dengue IgG and IgM antibodies [1] that should be improved significantly through concurrent assay for dengue NS1 antigen: dengue NS1 has had a diagnostic performance matching RT–PCR for dengue virus RNA. For example, dengue virus NS1 antigen detection in travelers upon arrival at airports in Taiwan was instrumental towards detection of 19 RT–PCR-negative travelers who would have been labeled dengue-negatives. Two of them turned out to be IgM-positive on days 17 or 18 of illness [2]. Furthermore, in Malaysia, 42 of 55 patients with an acute diagnosis of dengue were positive only for NS1 but were negative for both RT–PCR and viral isolation [3]. During the 2008 spurt in dengue cases in Delhi, a pilot study was made at the Sant Parmanand Hospital to establish utility or otherwise of dengue immunochromatographic kit for detection of NS1 antigen. Employing the dengue NS1 Ag strip (Bio-Rad, Marne-la-coquette), 22 samples from patients with suspected dengue were evaluated. Five patients were positive for NS1 antigen but were negative for dengue IgM and IgG. They were tested negative for dengue RT-PCR, details elsewhere [4], at the National Institute of Communicable Diseases, Delhi. The combined ImmunoComb Dengue IgG& IgM BiSpot kit only when converted into a tri-spot on-line spot assay kit would be ideal for a comprehensive and complete assessment and appreciation of dengue clinical status. Absence of positive control to monitor the working of the obtainable dengue NS1
Ag strip kits (Bio-Rad, Marne-la-coquette) has been rather awkward. A known positive control should be included in every commercial immunochromatographic (lateral flow) test strip kit including the future organics (Yavne, Israel) integrated NS1, IgG, and IgM assay format. Acknowledgment The technical assistance of Ms Beena Michael is acknowledged. References [1] Rivetz B, Siman-Tov, Ambal E, et al. New dengue antibody assay with unique differential detection of IgG and IgM antibodies. Clin Biochem 2009;42:180–4. [2] Shu PY, Yang CF, Kao JF, Su CL, Chang SF, Lin CC, et al. Application of dengue NS1 antigen rapid test for on-site detection of imported dengue cases at airports. Clin Vaccine Immunol 2009;16:589–91. [3] Zaniah S, Wahab AH, Mariam M, Fauziah MK, Khairul AH, Rosalina I, et al. Performance of a commercial rapid dengue NS1 antigen immunochromatography test with reference to dengue NS1 antigen-capture ELISA. J Virol Methods 2009;155:157–60. [4] Kumar M, Pasha ST, Mittal V, Rawat DS, Arya SC, Agarwal N, et al. Unusual emergence of Guate 98-like molecular serotype of DEN-3 during 2003 dengue outbreak in Delhi. Dengue Bull 2004;28:161–7.
Subhash C. Arya* Nirmala Agarwal Sant Parmanand Hospital, 18 Alipore Road, Delhi 110054, India E-mail address: [email protected] (S.C. Arya) *Corresponding author.
0009-9120/$ - see front matter © 2009 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.clinbiochem.2009.08.008
24 April 2009