HIV and HCV Co-infection continues to be a significant public health problem globally especially within high-risk groups. Monitoring viral loads with precision helps direct treatment choices and measure treatment success while preventing resistance to drugs. Traditional laboratory-based testing faces limitations due to restricted accessibility and dependence on centralized facilities along with the complex process of quantifying both HIV and HCV viral loads which impedes worldwide control measures for these viruses. We developed a portable self-testing device that measures HIV and HCV viral loads from a 100 μL finger-prick blood sample at the same time. The system combines RNA extraction with rapid multiplex RT-PCR to provide semi-automated testing capabilities and generate results in under 1 h. The system extracts RNA at 80 % efficiency and employs a three-channel optical detection system that detects as low as 5 copies per reaction while delivering high sensitivity and accuracy. Validated studies found a robust connection with Bio-Rad benchtop systems (R = 0.97-0.99) which verified that detection sensitivity and accuracy matched standard laboratory testing standards. The testing device enables parallel processing of four patients which results in enhanced efficiency and access to testing services. Individuals affected by HIV/HCV co-infection can use this self-testing solution to track their viral loads on their own to enable prompt treatment changes and lower transmission risks. The technology delivers an effective self-monitoring option for viral load management through its combination of precision, portability and an easy-to-use design which advances HIV and HCV treatment outcomes.