The Effect of Salicylate on Platelet Function in CKD (Chronic Kidney Disease) Patients Treated With Aranesp

Inclusion Criteria: * Chronic hemodialysis, peritoneal dialysis or CKD 5 treated conservatively * aged 18-85 * indication for treatment with Erythropoiesis-stimulating agents (ESA) Exclusion Criteria: 1. Known allergy to ASA 2. Known contraindication to ASA, e.g. recent bleeding episode. 3. Known indication for ASA. If the patient is being treated with ASA, and the physician does not find any indication for this treatment, this can be stopped, and the patient included after 4 weeks. 4. Raised reticulocyte count 5. Current anticoagulant therapy, e.g. warfarin, ADP receptor inhibitor (excepting short-term anticoagulant therapy in connection with dialysis) 6. Short expected length of life 7. Inability to give informed consent 8. Expected non-compliance 9. Active cancer - except for non-melanoma skin-cancer 10. Iron deficiency (defined as a reticulocyte Hgb \<1,8 fmol. Patients can be included when their iron deficiency has been cured. . 11. Change in ESA dosis \>33,3% within previous 2 month 12. Fertile women. Pregnancy is excessively rare in dialysis patients. Women who are \<50 years, or who are still menstruating will be excluded from the study. 13. Stable Aranesp ® dose \<20 µg/week.