| Clinical classification |
| C0: No visible or palpable signs of venous disease |
| C1: Telangiectases or reticular veins |
| C2: Varicose veins |
| C3: Edema |
| C4a: Pigmentation and/or eczema |
| C4b: Lipodermatosclerosis and/or atrophie blanche |
| C5: Healed venous ulcer |
| C6: Active venous ulcer |
| CS: Symptoms, including ache, pain, tightness, skin irritation, heaviness, muscle cramps, as well as other complaints attributable to venous dysfunction |
| CA: Asymptomatic |
| Etiologic classification |
| Ec: Congenital |
| Ep: Primary |
| Es: Secondary (post-thrombotic) |
| En: No venous etiology identified |
| Anatomic classification |
| As: Superficial veins |
| Ap: Perforator veins |
| Ad: Deep veins |
| An: No venous location identified |
| Pathophysiologic classification |
| Pr: Reflux |
| Po: Obstruction |
| Pr,o: Reflux and obstruction |
| Pn: No venous pathophysiology identifiable |
Adapted from Eklöf et al. Used with permission.