Yeah, looks like it should work. I would probably do something like this:

FUNCTION IsDup
LOCAL llDupRec

SELE LOCAL_HIV
SCATTER MEMO NAME oRecOne

SELE CDCHIV
SCATTER MEMO NAME oRecTwo

IF COMPOBJ( oRecOne, oRecTwo )
  *Duplicate
  llDupRec = .T.
ELSE
  *not a duplicate
  llDupRec = .F.
ENDIF

RETURN llDupRec

Good luck,
John