Blood donation and will screen for antibodies to less common antigens. More testing, including a crossmatch, is usually done before a transfusion. Type O negative is often cited as the "universal donor" but this only refers to red cell and whole blood transfusions. For plasma and platelet transfusions the system is reversed: AB positive is the universal platelet donor type while both AB positive and AB negative are universal plasma donor types. Most blood is tested for diseases, including some STDs. The tests used are high-sensitivity screening tests and no actual diagnosis is made. Some of the test results are later found
Jehovah's Witnesses and blood transfusions on blood transfusions has come from both members and non-members. A group of dissident Witnesses known as Associated Jehovah's Witnesses for Reform on Blood (AJWRB) states that there is no biblical basis for the prohibition of blood transfusions and seeks to have some policies changed. In a series of articles in the "Journal of Medical Ethics" US neurologist Osamu Muramoto, who is a medical adviser to the AJWRB, has raised issues including what he claims is coercion to refuse transfusions, doctrinal inconsistency, selective use of information by the Watch Tower Society to exaggerate the dangers of transfusions and the use