MSRA-2395
A 75-year-old man comes to the Medical Team after routine blood tests showed an acute kidney injury. He has a history of systemic lupus erythematosus (SLE) and is currently taking steroids. The renal team suspects acute interstitial nephritis (AIN). He has not been sick recently and is not taking any new medications.
What is the most appropriate investigation to perform for this patient’s diagnosis?