Renal, Urology and Electrolytescommon
A 63-year-old man who has smoked for 40 years and worked for 20 years in a tyre factory reports that on two occasions in the last month his urine has been bright red throughout the stream, without any pain, fever or difficulty passing urine. He has no flank pain. Examination, including the prostate, is normal. Urine microscopy shows > 500 red cells/µL with no casts and no growth on culture; his creatinine is 78 µmol/L.
Which one of the following is the most appropriate next step?