Colorimetric Detection of Dengue by Single Tube Reverse-Transcription-Loop-Mediated Isothermal Amplification

Lau, Yee-Ling; Lai, Meng-Yee; Teoh, Boon-Teong; Abd-Jamil, Juraina; Johari, Jefree; Sam, Sing-Sin; Tan, Kim-Kee; AbuBakar, Sazaly

Since LAMP does not require any major equipment, it represents an ideal diagnostic tool for use in areas with limited resources. A LAMP-based assay that requires the use of 4 reaction tubes for the detection of dengue virus was developed in 2005 by Parida et al. and RT-LAMP (Reverse transcription LAMP) was shown to be highly sensitive; however, it was tested on only 25 positive dengue samples and the specificity was only 93% [4] . To be cost effective, we developed a multiplex RT-LAMP method to detect dengue virus infections using a single tube. In addition, we used hydroxynaphthol blue (HNB) dye for the colorimetric detection of the loopmediated isothermal amplification reaction. One of the most attractive features of this RT-LAMP assay is that the HNB dye allows the test to be interpreted using the naked eye. This approach has been shown to be a sensitive and simple means of rapidly diagnosing turkey coronavirus infections either directly from feces or in association with virus isolation methods [5] .