1.抽无菌水0.2ml与青霉素混合摇匀
2.抽出0.1ml原液加0.9ml无菌水摇匀推出0.9ml剩余0.1ml液体
3.用剩余.0.1ml液体加无菌水0.9ml无菌水摇匀推出0.9ml剩余0.1ml液体
4.用剩余0.1ml液体加无菌水0.9ml无菌水摇匀则可进行皮试操作医学称:抽三推二