Inserting time in spreadsheet

[papabill]

Assuming your first Blood Level (242) is in cell B2, in cell C2 (col. Time) copy this formula.
=IF(ISBLANK(B2),"",IF(C2="",NOW(),C2))
When you fill in B2 and C2 is empty the time will fill in and will not change unless you empty B2 again.

I guess I should have gone into more detail.

There are a possibility of 12 "tests" a day, two columns, one for level, the other for time (each one for a 2 hour span), for every day in the month (this month has 31 days) The spreadsheet covers from B4..Y34. The "level" slots are B,D,F,H,J,L,N,P,R,T,V,and X, and the "time" slots are C,E,G,I,K,M,O,Q,S,U,W, and Y.

Each level goes in one column, and the time goes in the adjacent column (to the right). I only test every 4 hours or so, so of course I don't enter data in every cell.

I'm probably making this infinately harder, but it would be great if I could get a workable solution.

Thanks in advance.