Age more than 55 years, diabetes, high value of leukocytes, low value of cholinesterase, presence at CT of staghorn stone, pyonephrosis, air in the collecting system, fat stranding, renal, perirenal, pararenal, and psoas abscess, pleural effusion, and lung atelectasis resulted in the more clinically significant factors investigated for their ability to predict the diagnosis of XGP. The gene discussed is BCHE; the disease is Psoas abscess.