The lookup value has to be in the far left column of your lookup range.
Either adjust your lookup range or move the concatenated field so its in the
left most column.

=VLOOKUP(A2&B$1,C$35:E$38,2.False)

Hope this helps.

Bill Horton

"pm" wrote:

I've tried to illustrate my problem:

"NameID" is A1, "rs10170160" is B1, etc. Array data starts at A35

Name ID€¦..rs10170160
70001-1€¦..(formula here)

Formula: =vlookup(A2&B$1,A$35:E$38,4,False)

Array: (note, column C here is programmed in as =A35&B35)

70001-1€¦..rs10170160€¦..70001-1rs10170160€¦..C€¦..T
70001-11€¦..rs10170160€¦..70001-11rs10170160€¦..C€¦..T
70002-1€¦..rs10170160€¦..70002-1rs10170160€¦..C€¦..T
70002-13.....rs10170160.....70002-13rs10170160.....T.....T

Why does my formula keep returning NA when it should return a "C"??

Thanks in advance!