The Orthodox Church teaches that there are two types of Baptism: Baptism by Water and Baptism by Blood. Baptism by Water is by far the most common practice and is ideally accomplished by the candidate’s full immersion using the Trinitarian formula, “In the Name of the Father, and of the Son, and of the Holy Spirit.” However, in certain instances, a baptism may also be take place by either pouring or sprinkling the person with water. Each is considered valid.
Baptism by Blood refers to an instance when someone who is not a Christian accepts Christianity within a given moment, but is martyred for their faith before having had a chance to be baptized. In such instances it is said that their baptism is a baptism by “blood” and they are afforded all of the rights and privileges associated with Christian burial.
There is, perhaps, also a third type of baptism known as Baptism by Desire. This is when someone who wishes to be baptized and is perhaps enrolled in a catechetical program, unexpectedly dies prior to having received the Sacrament. Their intent may have been explicit (fully and clearly expressed) or implied. In such circumstances the clergy would deal with each situation on a case by case basis.