A number of laboratory tests must be completed before blood or blood products can be transfused:

• Determination of the blood type with a crossmatch.
  
• Screening for antibodies that may produce adverse effects if transfused.
  
• Screening for possible infectious agents that could be transmitted with transfusion.
  

The following tests are manadatory on all units of blood collected for transfusion:

• ABO group and Rh type
  
• Screening for blood-group antibodies
  
• Serologic test for syphilis
  
• Serologic tests for human retroviruses including:
  
  • HIV-1
    
  • HIV-2
    
  • HTLV I
    
  • HTLV II
    
• Serologic tests for hepatitis including:
  
  • Hepatitis B
    
  • Hepatitis C
    

If, and only if, all of these markers are negative can blood be conveyed to the Blood Bank for storage until usage. A postive results for some of these tests may prevent further donation by that person. A person with such a test result will be notified by the donor center. Persons with a potential medical condition should see a physician and should not, under any circumstance, donate only to have blood tested. These measures are done to make the blood supply as safe as possible. The significant infectious diseases transmitted by transfusion and the risk of transmission (RT) in the U.S. are given below.