Duplicate records in SDTM LB

I have entered the key variables that define a unique record in our SDTM LB, in Datasets tab of the excel spec. But I still receive duplicate warnings on a different set of variables(LBDRVFL, VISITNUM, LBDTC, LBTESTCD, LBSCAT, USUBJID, LBSPEC, LBCAT) in validation report. I had include the xml in my validator too. How do I get rid of these duplicate warnings? Thanks