Will a bladder biopsy help my doctor figure out if my bladder infection is very serious?

Maybe: Bladder biopsies help identify malignancy in the bladder. If there is concern for infection, then a urine culture is needed to identify the type of infection and medicaiotns that will be effective in trating the infection. A biopsy by itself will not generally tell you about an routing bladder infection.

Its Contraindicated: Unless a cystoscopy must be perfomed emergently, the procedure is contraindicated in the presence of a bladder infection. A cystoscopy and bladder biopsy could lead to a massive infection, sepsis, and possibly death if performed while there is an untreated urinary infection.