why do inject 3 diluent injections after the completion of Std Solution in the Carry over test.....? Example : 1) Diluent as blank 2) 5ul std solution 3)Diluent as Blank 4)Diluent as Blank 5)Diluent as Blank

why do inject 3 diluent injections after the completion of Std Solution in the Carry over test.....? Example : 1) Diluent as blank 2) 5ul std solution 3)Diluent as Blank 4)Diluent as Blank 5)Diluent as Blank Is any Reason Please Explain ME.?