Methods and devices for determining the healing status of wounds, in particular of chronic wounds are provided. Also provided are kits comprising the diagnostic devices, and methods of wound diagnosis and treatment using the diagnostic devices and methods. A diagnostic apparatus (device) for monitoring wounds that exude a wound fluid and determining whether said wounds would be responsive to treatment with wound therapy such as oxidized cellulose therapy is also provided along with kits comprising the diagnostic apparatus and a wound dressing. Furthermore, methods of prognosing and treating wounds that exude a wound fluid are also provided.