title: Reverse transcription loop-mediated isothermal amplification (RT-LAMP) for diagnosis of dengue.
abstract: BACKGROUND
  Dengue is an emerging public health problem causing serious morbidity and mortality in tropical developing countries. Early, sensitive and specific diagnosis is paramount for clinical decision making. Currently available diagnostic tests are limited in scope and utility. This study highlights applicability of RT-LAMP in dengue diagnosis.
  
  
  METHODS
  100 dengue confirmed cases, 100 dengue negative cases and 79 healthy negative controls from dengue epidemic between Sep 2009 to Jul 2011 were included. Dengue cases were profiled using WHO guidelines 2006, haematological and biochemical parameters evaluated and diagnosed using NS1 antigen, IgM and IgG enzyme immunoassay, RT-PCR and RT-LAMP. Positive cases were serotyped, genotyped and various tests were compared.
  
  
  RESULTS
  Mean haematocrit, PT, PTT, platelet count, activated lymphocytes, serum fibrinogen, transaminases, bilirubin, lactate dehydrogenase, protein and sodium were significantly elevated in DHF/DSS as compared to DF. NS1 antigen, RT-PCR and RT-LAMP were sensitive during 1-3 days while μ-capture IgM EIA was specific after 5-7 days of initial infection. DEN-1 genotype III was predominant.
  
  
  CONCLUSIONS
  Deranged haematocrit and liver function tests are indicators of the severity of the disease. RT-LAMP is rapid, cost effective, highly sensitive and specific qualitative and quantitative technique which can detect dengue infection in both early and intermediary stages when NS1 antigen titres are not in the detectable range and the IgM antibody titres have just started to rise. Its superiority over existing techniques, amenability for automation and promising utility in low resource healthcare setups and field conditions raise it as the new gold standard for dengue diagnosis.
authors.affiliation: Prof & HOD, Dept of Microbiology, AFMC, Pune 411040, India.
authors.forename: Ajay Kumar
authors.initials: AK
authors.lastname: Sahni
authors.affiliation: Associate Professor, Dept of Microbiology, AFMC, Pune 411040, India.
authors.forename: Naveen
authors.initials: N
authors.lastname: Grover
authors.affiliation: Consultant & Head, Dept of Haematology & Stem Cell Transplantation, Army Hospital (R&R), New Delhi 110010, India.
authors.forename: Ajay
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Resident (Microbiology), Dept of Pathology and Molecular Medicine, Army Hospital (R&R), New Delhi 110010, India.
authors.forename: Inam Danish
authors.initials: ID
authors.lastname: Khan
authors.affiliation: Professor, Community Medicine, Maulana Azad Medical College, New Delhi, India.
authors.forename: Jugal
authors.initials: J
authors.lastname: Kishore
keywords: Dengue; Gold standard; Reverse transcriptase polymerase chain reaction (RT-PCR); Reverse transcription loop-mediated isothermal amplification (RT-LAMP)