alternative to "" when using in Macros

Hi,

I have this formula, which contains multiple "" when looking to see if text is in the cell : 

=IF(ISNUMBER(SEARCH("Sling",D6)),"Sling/Lab",IF(ISNUMBER(SEARCH("Dress",D6)),"Dressing",IF(ISNUMBER(SEARCH("Downtime",D6)),"Downtime",IF(ISNUMBER(SEARCH("jigs",D6)),"Jigs",IF(ISNUMBER(SEARCH("NC",C6)),"NCR",IF(ISNUMBER(SEARCH("M2",C6)),"Change",IF(ISNUMBER(SEARCH("M3",C6)),"Change","Earning")))))))

however when I use it in a macro, the formula has to be in quotation marks and so it creates an error in the formula, is there any way to still have text in the formula?