"IF(A2=A1+1;B1+1;1)", possible to recognize same date? it's an ICU research

Hi!
Have a file with 46000 cells in 8 columns. I have diffrent days that we taken some exams and to make a diagram we have to make the dates match so we can compare the test we've taken.
Tryed to use the IF formula "IF(A2=A1+1;B1+1;1)" but my problem is that we have taken several diffrent test of same patient( have a column with their ID).

What I need help with is to make some changes to the formula so it can recognize same date with same patient and give it same number instead of starting back att 1!

Would really be greatful if some of you smart guys could help me!
Thanks in advance

you need to define your problem in a better way so that we can work on it. why not post the sample sheet and tell us what output you want.
A V Veerkar