Ontario OHIP diagnostic codes — physician reference for FHO/FHN billing and acuity optimization. The MOH diagnostic code list uses terminology from the 1970s. Common conditions including COPD, atrial fibrillation, GERD, ADHD, PCOS, HPV, long COVID, and dyslipidemia are routinely miscoded or impossible to find because modern clinical terms do not appear in the official labels. For FHO+ and FHN physicians in Ontario, undercoded conditions are invisible to the Ministry’s acuity calculation and directly affect capitation rates. This free searchable reference — built by the physicians at Ajax Harwood Clinic in Ajax, Ontario — maps modern clinical language, abbreviations, and brand names to the correct MOH diagnostic codes, with a built-in FHO+ acuity band guide identifying which codes carry the highest capitation weight.