10 grams of the chemicals necessary for brentamine blue spot tests for acid phosphatase activity. Premixed powder. Weigh and add water to obtain a buffered (pH 5.0) reagent containing brentamine dye and alpha napthyl phosphate substrate. Wait 5-10 minutes for the dissolved reagent to turn to a tan/beige color before using. Reconstituted reagent stable and sensitive for one day’s use. Store powder frozen.