All 50 states require a couple to do certain things before a marriage license is issued.
Blood tests One of the most common is a blood test.
The blood test is needed to tell if either party has a venereal disease or measles. States are divided between those that require a blood test and those that don't. The reasoning was people could change their minds if they thought the upcoming marriage might be a mistake. Although most states require that a ceremony be conducted before the couple is considered man and wife, they don't specify what type of service. Either a civil or a religious ceremony is acceptable.