Calciphylaxis in Patients With Chronic Kidney Disease - A Study of the Danish Calciphylaxis Research Initiative (DanCaRI)

Inclusion Criteria: Cases * Age ≥18 years. * CKD. * Suspicion of calciphylaxis or newly diagnosed calciphylaxis episode. The suspicion or diagnosis of calciphylaxis is a mutual decision of the involved medical specialties (nephrologist, dermatologist, pathologist, other). * Ability to give informed consent. * Ability to participate in a clinical study as assessed by the local investigator. * Provides written informed consent. Controls * Age ≥18 years. * CKD * Ability to give informed consent. * Ability to participate in a clinical study as assessed by the local investigator. * Provides written informed consent. Healthy reference group * Age ≥18 years. * Self-assessed as healthy, confirmed by local investigators at inclusion Exclusion Criteria: Cases \- the calciphylaxis diagnosis becomes excluded Controls - Being diagnosed with calciphylaxis Healthy controls Up to 60 years of age: eGFR below 60 ml/min/1.72m2. \- Over 60 years of age: eGFR below the 95% confidence interval for eGFR adjusted for age (Danish Society of Nephrology references ranges)