Question: I’m looking at codes from category L89- (Pressure ulcer), and I’m trying to figure out which character designates the pressure ulcer stage. Can you help me? Maine Subscriber Answer: The sixth character of the L89- codes identifies the pressure ulcer stage. ICD-10-CM classifies pressure ulcer stages based on severity, which is designated by stages 1-4, deep tissue pressure injury, unspecified stage, and unstageable. The different stages are as follows: