What history of falls ICD code can I use?
If you're looking for history of falls ICD codes, there is only one that you can use, and that is Z91.81 - History of falling.
As its name suggests, this is meant to be used on a patient confirmed to have fallen before, whether once or several times.
This ICD-10 code is considered unacceptable as a principal diagnosis because it isn't diagnosing anything in the first place. It's an ICD-10 code explaining a person's health condition.
For example, you're handling an elderly patient who cannot walk because they injured their right leg. Let's stipulate that it's broken. The principal diagnosis for that should be something like S82.111A - Displaced fracture of right tibial spine, initial encounter for closed fracture. During the examination of this problem, the patient mentioned that they had fallen several times before, which resulted in their inability to walk for now. You can use Z91.81 - History of falling to support the principal diagnosis because it explains why the patient broke their right leg. It was due to several falls, each making it more susceptible to breaking.