This document discusses developing an item set from the International Classification of Functioning (ICF) to understand patient functioning for multimorbid patients in general practice. It notes that while diagnoses show medical issues, they do not capture patient functioning. The researchers conducted a study with GPs to identify which ICF items are most relevant to register for multimorbid patients and the willingness of GPs to record this information. The study found some but not full agreement among GPs on useful functioning items, and concluded that the ICF-based approach is viable and could be applied in other GP studies.