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Blood Type Test


Blood type tests are done before a person gets a blood transfusion and to check a pregnant woman's blood type. The following table shows the compatibility of blood types between blood donors and recipients.

Read the table as follows: A person who has A-negative blood can receive A-negative or O-negative blood.

Blood types that match
A person who has: Can receive:

A- blood

A-, O- blood

A+ blood

A-, A+, O-, O+ blood

B- blood

B-, O- blood

B+ blood

B-, B+, O-, O+ blood

AB- blood

AB-, O- blood

AB+ blood

AB-, AB+, A-, A+, B-, B+, O-, O+ blood

O- blood

O- blood

O+ blood

O-, O+ blood

Minor antigens (other than A, B, and Rh) on the red blood cells are also checked for a match before a blood transfusion.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

What To Think About

  • Severe transfusion reactions are rare today because blood type is always done before a person receives a blood transfusion.
  • Blood type may be done to check the identity of birth parents. For example, in a paternity case, if the blood types of a mother and her child are checked against blood types of the possible fathers, the real father can sometimes be found by the blood type match. But blood type is more useful in proving that a man is not the father than it is in proving that he is the father. Other tests, such as a human leukocyte antigen (HLA) type, may be done. To learn more, see the topic Human Leukocyte Antigen (HLA).

Related Information


  1. Stanford University School of Medicine (2011). Blood types in the U.S. Available online:

Other Works Consulted

  • Chernecky CC, Berger BJ (2013). Laboratory Tests and Diagnostic Procedures, 6th ed. St. Louis: Saunders.

  • Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.

  • Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.

WebMD Medical Reference from Healthwise

Last Updated: September 09, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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