In the 19th century, scientists were unaware that people had different blood types. After the discovery of the differences in red blood cells, blood testing became an important part of screening for blood banks. In the 1930s and 1940s, premarital blood testing for syphilis and rubella became standard. Today, it is possible to screen blood for many different types of bloodborne diseases including HIV, hepatitis and West Nile virus.

Early Transfusions

The first blood transfusion in recorded history took place in 1665. Before the discovery of blood typing, doctors did not perform any screening tests before a transfusion. Some early blood transfusion devices were nothing more than a tube system to transport blood from the donor directly into the veins of the recipient. Without understanding blood types, success was hit or miss. Sometimes the recipient’s body would reject the donor’s blood, and doctors could not explain why.

Blood Typing

In 1901, Karl Landsteiner published a medical paper identifying three blood types–A, B and C (later changed to O) 1. One year later, his colleagues Alfred Decastello and Adriano Sturli added AB as the fourth and final blood type. Although scientists already understood there were differences in the composition of blood, Landsteiner discovered that human blood is not universally compatible because our immune systems produce antibodies to blood of another type. Landsteiner later won the Nobel Peace Prize for his groundbreaking blood research.

Blood Type Testing

After discovering blood types, it became universal to screen for type before blood transfusions. According to Cascade Regional Blood Services, Landsteiner discovered the Rh factor in blood in 1939, which was considered the second greatest breakthrough in blood research since his earlier discovery of the ABO blood type. It was now possible to screen blood for type and Rh factor (ie: A-positive or A-negative) to provide safe transfusions.

Bloodborne Disease Testing

To protect the blood supply, blood banks routinely test for various kinds bloodborne illnesses. Blood was first tested for hepatitis B in 1971 and for HIV in 1985. Today, blood is tested for syphilis, hepatitis C, West Nile virus and other diseases. Blood tests also can help a doctor identify various types of illnesses in patients, including anemia, diabetes and malaria.

Blood Testing and Marriage

In the 1930s and 1940s, blood testing to screen for syphilis and/or rubella became a prerequisite for obtaining a marriage license in most states. According to Dr. Robert H. Shmerling of Beth Israel Deaconess Medical Center, sexually transmitted diseases were extremely common in those days. Premarital blood tests identified those who were infected and gave them a chance to seek medical treatment before infecting their future spouse. While rubella is not a serious disease for adults, it can be extremely dangerous to an unborn fetus. Premarital testing for rubella was designed to protect the health of a newlywed couple’s unborn children. Today, a few states still require a blood test prior to issuing a marriage license.