Diagnostic uncertainty in nursing homes (NH) drives physicians to prescribe antibiotics (AB) for suspected lower respiratory tract infections, whereas part of these prescriptions are not required. We hypothesize that C-reactive protein (CRP) point-of-care testing (POCT) provides more diagnostic certainty, and will lead to better AB stewardship and reduced AB use in NHs. The current proposal includes a cluster RCT to test this hypothesis. In addition, we aim to investigate: 1) associations between CRP POCT values and clinical features and AB use, 2) cost-effectiveness and cost-benefit of CRP POCT use in the NH setting, and 3) potential facilitators and barriers for CRP POCT use in the NH setting, to guide the development of an implementation strategy. Implementation of CRP POCT in NHs may have substantial benefits for both individual patients (better management, less exposure to side-effects of AB and drug-interactions) and public health (less AB resistance development).