19th May 2025

You are reviewing Mrs Patel, a 54-year-old patient in the Emergency Department.

You are reviewing Mrs Patel, a 54-year-old patient in the Emergency Department. She has presented with fever, joint pain and a rash, which developed shortly after she was commenced on allopurinol for gout, and her blood tests show a significant decline in her glomerular filtration rate from baseline. You suspect drug-induced acute interstitial nephritis. Which blood test finding is most in keeping with this diagnosis? 

Select the SINGLE most appropriate option from the list below. Select ONE option only.