Okay but remember, after you open it to test it, the top of the nitrite will oxidize into nitrate. When you plan to ctb with it, dispose of the top layer of the SN. Also, the blood test only proves that there is nitrite in the substance rather than proving the purity of it so just because your blood quickly changes to a chocolaty colour, doesn't mean that the SN is pure!
I'm glad the SN arrived for you, it must be relieving knowing that your bus has arrived.