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J Clin Virol. 2013 Sep;58(1):127-31. doi: 10.1016/j.jcv.2013.06.006. Epub 2013 Jul 1.

Multiplex loop-mediated isothermal amplification (M-LAMP) assay for the detection of influenza A/H1, A/H3 and influenza B can provide a specimen-to-result diagnosis in 40 min with single genome copy sensitivity.

Author information

1
Department of Pathology and Molecular Medicine, McMaster University, Canada; Regional Virology & Chlamydiology Laboratory, St. Joseph's Healthcare Hamilton, Hamilton, Ontario L8N 4A6, Canada. mahonyj@mcmaster.ca

Abstract

BACKGROUND:

Rapid isothermal amplification methods have recently been introduced and they offer significant advantages over PCR.

OBJECTIVE:

To develop a rapid and sensitive M-LAMP assay for the detection of influenza A (H1 and H3) and B that does not require RNA extraction.

STUDY DESIGN:

We designed six primers targeting the matrix genes of influenza H1 and H3 and the NS1 gene of influenza B and developed a M-LAMP assay using a commercially available Master Mix and a real time fluorometer (Genie II, Optigene, UK) that displays real time amplification, time to positivity and amplicon annealing temperature (Tm). M-LAMP was evaluated against PCR by testing 202 nasopharyngeal (NP) specimens.

RESULTS:

Optimized M-LAMP was rapid with a mean amplification time of 12 min (compared with 90-120 min for PCR), had an analytical sensitivity of 1 genome equivalent (ge), and could distinguish influenza A including subtypes A/H1 and A/H3 from influenza B by Tm. M-LAMP detected 26/28 influenza A/H1, 27/27 influenza A/H3 and 39/39 influenza B specimens and had a combined sensitivity and specificity for detecting influenza (A and B) of 97.9% (92/94) and 100% (108/108), respectively. The rapid amplification time of LAMP coupled with a novel 10-min specimen preparation procedure consisting of vortexing and heating in M-Swab diluent (Copan Italia) provided a rapid result.

CONCLUSIONS:

M-LAMP had excellent sensitivity and specificity for detecting influenza A and B in NP specimens and when used together with a rapid specimen processing method provided a specimen-to-result diagnosis in 30 min.

KEYWORDS:

Influenza; LAMP; Rapid detection

PMID:
23827787
DOI:
10.1016/j.jcv.2013.06.006
[Indexed for MEDLINE]

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