Hi Blood info Thanks for getting in touch with BioSure and thanks for asking an interesting question. The biggest reason for wiping away the first drop of blood is to avoid contamination of the sample. Research has shown that actually simply washing your hands first and ensuring that they are dry before taking the blood is at least as effective. The BioSure HIV Self Test only requires a tiny amount of sample to work but this is best collected from a well formed drop of blood. Taking the first drop of blood from a clean skin surface is the best way to ensure that you can easily create a well formed drop of blood. I hope that this answers your question. Kind regards Gary Carpenter BioSure (UK) Limited