ABO Blood Typing

Definition
Purpose
Description
Precautions
Risks
Side effects
Interactions

Definition

Of the many different bases for typing blood, the most commonly used and the most important are the ABO groups. Specific combinations of antigens and antibodies defines the blood type of all humans and many primates.

Purpose

The purpose of the ABO typing system is to allow successful sharing of blood and blood products by avoiding rejections after transfusions.

Description

The ABO blood groups were discovered by Karl Landsteiner in 1900 and 1901 at the University of Vienna. All humans and most other primates can be

WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?

ABO blood typing involves personnel from several allied health disciplines. A phlebotomist usually obtains an initial blood sample. A medical technologist typically runs the tests to determine specific blood types. A physician or surgeon commonly prescribes blood or blood products. A nurse typically administers the blood or blood products to a recipient.

typed using the ABO blood group system. Four principal blood types have been defined on the basis of antigens and antibodies.

• Type A blood is positive for antigen A and anti-B antibody and is negative for Antigen B and anti-A antibody.
• Type B blood is positive for antigen B and anti-A antibody and is negative for Antigen A and anti-B antibody.
• Type O blood is negative for both antigen A and antigen B and is positive for both anti-A antibody and anti-B antibody.
• Type AB blood is positive for both antigen A and antigen B and is negative for both anti-A antibody and anti-B antibody.

The presence or absence of antigens and antibodies determines the type of blood that a person can give (donate) or receive. People will not destroy blood of their own type but will destroy other types of blood. For example, the absence of anti-A antibodies allows people with type A blood to receive type A blood. However, the anti-B antibodies in type A blood will destroy type B blood. This immune system mechanism protects people from alien organisms.

Individuals with type O blood do not produce any ABO antigens. As a consequence, their blood usually will not be rejected when it is given to others with different ABO types. People with type O blood are called universal donors for transfusions. However, they can only receive type O blood. Persons having type AB blood do not have any ABO antibodies. They are universal receivers for transfusions, but their blood will be rejected when given to people with every other type because they produce both kinds of antigens.

KEY TERMS

Agglutination— An immunochemical reaction. It is termed positive when two chemicals that are mixed cause clumps to form.

Hematoma— An accumulation of blood outside of the circulatory system

Phlebotomist— a person trained to obtain a blood sample.

Rhesus factor— A secondary component of ABO typing that was first observed in rhesus monkeys.

To determine an individual’s ABO type, serum containing anti-A antibodies is mixed with a few drops pf their blood. Another serum containing anti-B antibodies is mixed with a different few drops of blood. The results determine the ABO type by a process of elimination.

ABO blood types are inherited through genes on chromosome 9, and they do not change as a result of environmental influences during life.

The Rhesus factor is a associates with ABO blood typing. This further describes the reactivity of each type. The Rhesus factors are positive (+) and negative (-). The Rhesus factor is abbreviated as Rh. The Rh factors of a donor and recipient must match to avoid sensitization or rejection. Thus, for example, type O blood includes O + and O-. Including the Rh factor, the ABO system includes 8 different blood types: A +, A-, B +. B-, AB +, AB-, O + and O-.

Precautions

ABO typing is not routinely used to determine genetic inheritance patterns from their parents. In fact, paternity in the U.S. and many other nations can no longer be legally established based on conventional blood typing. HLA types or DNA sequencing are more precise than ABO typing. DNA is the most costly test to use.

Risks

The risks associated with obtaining a blood sample are minimal. They include fainting, feeling lightheaded, pain from the needle used to obtain a blood sample (venipuncture), bleeding at the site of venipuncture, blood accumulating at the venipuncture site (hematoma), and infection.

Side effects

The most common physical side effect of ABO typing is a bruise at the site of venipuncture used to obtain a blood sample. A lab error has the potential to sensitize or kill a recipient if blood of the wrong type is given.

Interactions

ABO blood typing does not interact with pharmaceutical products.

Resources

BOOKS

Fischbach, F. T. and M. B. Dunning. A Manual of Laboratory and Diagnostic Tests. 8th ed. Philadelphia: Lippincott Williams & Wilkins, 2008.

McGhee, M. A Guide to Laboratory Investigations. 5th ed. Oxford, UK: Radcliffe Publishing Ltd, 2008.

Price, C. P. Evidence-Based Laboratory Medicine: Principles, Practice, and Outcomes. 2nd ed. Washington, DC: AACC Press, 2007.

Scott, M.G., A. M. Gronowski, and C. S. Eby. Tietz’s Applied Laboratory Medicine. 2nd ed. New York: Wiley-Liss, 2007.

Springhouse, A. M.. Diagnostic Tests Made Incredibly Easy!. 2nd ed. Philadelphia: Lippincott Williams & Wilkins, 2008.

PERIODICALS

Cho, D., J. S. Lee, M. H. Yazar, et al. “Chimerism and mosaicism are important causes of ABO phenotype and genotype discrepancies.” Immunohematology 22, no. 4 (2006): 183–187.

Deng, Z. H., J. Q. Zeng, Q. Yu, et al. “Genotyping of samples lacking expected antibodies in ABO blood group.” Journal of Clinical Laboratory Analysis 21, no. 6 (2007): 363–366.

Fung, M. K., K. A. Downws, and I. A. Shulman. “Transfusion of platelets containing ABO-incompatible plasma: a survey of 3156 North American laboratories.” Archives of Pathology and Laboratory Medicine 131, no. 6 (2007): 909–916.

Grim, S. A., T. Pham, J. Thielke, et al. “Infectious complications associated with the use of rituximab for ABO-incompatible and positive cross-match renal transplant recipients.” Clinical Transplantation 21, no. 5 (2007): 628–632.

Yazer, M. H., and D. J. Triulzi. “Immune hemolysis following ABO-mismatched stem cell or solid organ transplantation.” Current Opinions in Hematology 14, no. 6 (2007): 664–670.

ORGANIZATIONS

American Association for Clinical Chemistry. http://www.aacc.org/AACC/.

American Society for Clinical Laboratory Science. http://www.ascls.org/.

American Society of Clinical Pathologists. http://www.ascp.org/.

College of American Pathologists. http://www.cap.org/apps/cap.portal.

OTHER

American Clinical Laboratory Association. “Information about clinical chemistry.”2008 [cited February 24, 2008]. http://www.clinical-labs.org/.

Clinical Laboratory Management Association. “Information about clinical chemistry.” 2008 [cited February 22, 2008]. http://www.clma.org/.

Lab Tests On Line. “Information about lab tests.” 2008 [cited February 24, 2008]. http://www.labtestsonline.org/.

National Accreditation Agency for Clinical Laboratory Sciences. “Information about laboratory tests.” 2008 [cited February 25, 2008]. http://www.naacls.org/.

L. Fleming Fallon, Jr, MD, DrPH