For Procedure A the detection limit of the Lactose/Galactose Assay Kit (Rapid) is 2.96 mg/L of lactose and 1.48 mg/L of D-galactose, which is derived from an absorbance difference of 0.020 with the maximum sample volume of 1.00 mL.
For procedure B a further 8.5 dilution factor must be accounted for.