A critical bottleneck for equitable access to population-scale molecular diagnostics is the limited availability of rapid, inexpensive point-of-care tests especially in low- and middle-income countries. Here, we developed an open-sourceReverse transcription loop-mediated isothermal amplification(RT-LAMP) molecular assay for the detection of respiratory RNA virus infections. It is based on non-proprietary enzymes, namely HIV-1 reverse transcriptase,BstLF DNA polymerase and UDG BMTU thermolabile uracil DNA glycosylase. Formulated as liquid or lyophilized reaction mixtures, these reagents enable sensitive colorimetric detection of respiratory samples without the need for prior nucleic acid isolation. We evaluated our open-source lyophilized RT-LAMP assay on clinical samples with suspected COVID-19 infection, demonstrating high sensitivity and 100% specificity compared to the gold standardReverse transcription quantitative polymerase chain reaction (RT-qPCR). Reaction performance was unaffected by prolonged storage of lyophilized reagents at ambient or elevated temperatures. As a proof of concept, we evaluated the robustness and ease-of-use of lyophilized RT-LAMP reaction mixes through independent laboratory testing of COVID-19 samples in Ghana. Overall, our open-source RT-LAMP assay provides a flexible and scalable point-of-care test that can be adapted for rapid detection of various pathogens in resource-limited settings.