My father is 60 years old and slim. He does not have any problems in health before until this month. He experiences fatigue , headaches and poor appetite. I also noticed that he becomes much thinner. We went to the doctor today and did a blood exam. Here are the significant results :Urea 35 mmol/L, Creatinine 943 mmol/L, AST 16 U/L, ALT 17 U/L, ESR 70mm/hr, RBC 2.04 x10^12/L, Hemoglobin 66 g/L and hematocrit 18%. What do you think my father is experiencing now?