mutate with multiple conditions using if_else or ifelse

I'm trying to create a new variable "lab_conf" based on meeting either condition for 2 other variables "diagnosis" and "PC_R". This is the code I'm using:

mutate(lab_conf = ifelse( (diagnosis == "confirmed")|(PC_R == "pos"), "pos", "neg"))

The output I'm getting is showing NA where it should show "neg", so I'm only getting 2 values; "pos" or "NA". I'd like the values for this new variable to be either "pos", "neg", or NA based based on the conditions specified, where NA would be if its NA in both conditions.