Counter in code

Can someone please help me with the following?

I am currently using a countblank formula

when the sheet opens I store the number from the countblank formula

then when I call a procedure, if the number from the formula is less I know that something has been added.

I am currently using a sheet with a formula

Is there anyway to store the number in vba only

so

when the sheet opens, a code checks for the number of blank cells in range (e.g. Sheet 1 A1:Z1)
and stores that number

then when you call your procedure

if the current number of blank cells in less than the stored number on open then it will let you know

thansk

Josh