<s>[INST] Hi my brother in law is being investigated for stage 3 ckd. they are testing his urine for egfr and psa/acs. He stated that his blood pressure was within normal limits . The doctor only tested his blood initially due to  him having chest pain. What could be the cause of this [/INST] Hello,Most common cause of chest pain renal problem in patients is due to pleural effusion. My advice is to take him for a chest x-ray immediately.Hope I have answered your query. Let me know if I can assist you further.Regards,Dr. Siva Kumar Reddy </s>