Normal Goat Serum, Cat. No. S-1000, is essentially spun whole blood, filtered, heat inactivated and preserved with the addition of sodium azide. The 20 ml provided therefore is all goat serum. For most IHC and IF tissue staining applications, an aliquot is taken and diluted in assay buffer such as PBS or TBS to 2-10% (v/v). This working solution can be stored in the fridge and used for up to one week. Beyond this time, there would be concern for possible microbial contamination that would affect performance.