Background Despite successful vaccination programmes meningococcal disease (MD) remains the leading infectious cause of septicaemia and death in children in the UK and Ireland.^1,2 The early diagnosis of MD significantly improves outcomes with reduced morbidity and mortality.^1,2 The early stages of MD are often indistinguishable from a simple viral illness making an early positive diagnosis of MD difficult.¹ Hibergene have developed a commercially available bedside Loop-mediated isothermal AMPlification PCR (LAMP-MD) test that is a highly sensitive 0.89 (95%CI 0.72–0.96) and specific 1.0 (95%CI 0.97–1.0) for identifying children with invasive MD (4) (figure 1).

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Figure 1

Aims The aims of this RCEM funded study were:

• Assess the ease of use and suitability for the ED

• Determine the time taken to perform the test

• Independently verify LAMP-MD performance against TaqMan quantitative PCR.

Method The LAMP-MD was assessed for practicality and ease of use within the ED including an assessment of training needs, footprint and health and safety requirements.

For verification of the Hibergene LAMP-MD analyser and assay we used dry nasopharyngeal swabs sent for viral screening. Additional verification was undertaken using N. meningitidis genomic DNA spiked over a range of concentrations. This included serotypes A, B, C, W, X and Y and a dilution series to determine the limit of detection. All samples were then analysed using real time TaqMan qPCR.

Results

• The LAMP-MD analyser was easy to use and could be accommodated in the ED

• The mean time for detection of Meningococcal DNA was 14.01 min

• Detection of meningococcal serogroups A, B, C, W, X and Z was confirmed

• The detection limit for dry nasopharyngeal swabs was below 2 genomic copies per µl

• No non-specific amplification was observed in 17 randomly selected negative clinical swabs

• The LAMP-MD assay was 100% sensitive and specific relative to real-time TaqMAN PCR.

Conclusion LAMP-MD is a practical, rapid point of care test that can reliably detect all Meningococcal serotypes in less than 15 min.

Funding has been secured to perform a PERUKI supported study to investigate the potential for LAMP-MD in the diagnosis of meningococcal disease in children.

References

1. Meningitis Research Foundation. Meningococcal Meningitis and Septicaemia Guidance Notes2014.

2. Ó Maoldomhnaigh, et al. Invasive meningococcal disease in children in Ireland. PMID: 27566800.

3. NICE. Management of petechial rash.

4. Bourke TW, et al. Diagnostic accuracy of loop-mediated isothermal amplification as a near-patient test for meningococcal disease in children. PMID: 25728843.