Field deployment of a mobile suitcase laboratory for Buruli ulcer diagnosis in Ghana

Molecular diagnostics are the gold standard laboratory confirmation test for Buruli ulcer (BU), a severe necrotising skin disease caused by Mycobacterium ulcerans (M. ulcerans). However, current molecular tests are often performed outside endemic areas, which results in delayed diagnosis and increased patient management costs. To overcome these challenges and facilitate rapid diagnosis of clinically suspected BU lesions in affected communities, we developed a portable laboratory platform contained in two Pelican cases (each measuring 56 cm × 45.5 cm × 26.5 cm). We evaluated the feasibility of performing our earlier developed M. ulcerans Recombinase Polymerase Amplification (Mu-RPA) assay, along with a rapid DNA extraction method, using this mobile suitcase laboratory at BU clinics (BU-RPA mobile laboratory) in three endemic districts of Ghana. In the field, the entire process from sample collection to DNA extraction and amplification was completed in under one hour with this mobile setup. Among 39 PCR-confirmed BU cases, 32 (82%; 95% confidence interval [CI]: 67-91) were accurately identified by the BU-RPA mobile laboratory platform. All non-Buruli ulcer cases tested negative, resulting in a clinical specificity of 100% (95% CI: 90-100). Diagnostic performance varied by sample type: swabs demonstrated a sensitivity of 91%, whereas fine-needle aspirates (FNA) had a sensitivity of 69%. This mobile laboratory platform provides an effective workspace for the rapid, on-site diagnosis of BU, enabling timely results for healthcare providers at treatment centres. This mobile suitcase laboratory, together with its isothermal assays, presents a promising alternative to PCR for the swift diagnosis of suspected BU cases as well as other neglected tropical diseases in resource-limited settings.