ABO Incompatibility

A, B, and O are the three major blood types. The types are
based on small substances (molecules) on the surface of the
blood cells.
When people who have one blood type receive blood from
someone with a different blood type, it may cause their
immune system to react. This is called ABO incompatibility.
CAUSES.
The different blood types are:
*. Type A
*. Type B
*. Type AB
*. Type O
People who have one blood type may form proteins
(antibodies) that cause their immune system to react against
one or more of the other blood types.
Being exposed to another type of blood can cause a reaction.
This is important when a patient needs to receive blood
(transfusion) or have an organ transplant. The blood types
must be matched to avoid an ABO incompatibility reaction.
For example:
*. A patient with type A blood will react against type B or type
AB blood.
*. A patient with type B blood will react against type A or type
AB blood.
*. A patient with type O blood will react against type A, type
B, or type AB blood.
*. A patient with type AB blood will NOT react against type A,
type B, or type AB blood.
Type O blood does not cause an immune response when it is
received by people with type A, type B, or type AB blood. This
is why type O blood cells can be given to patients of any
blood type. People with type O blood are called "universal
donors.". However, people with type O can only receive type O
blood.
Both blood and plasma transfusions must be matched to
avoid an immune reaction. Before anyone receives blood, both
the blood and the person receiving it are tested carefully to
avoid a reaction. Usually a reaction occurs because of a
clerical error.
SYMPTOMS.
The following are symptoms of ABO incompatible transfusion
reactions:
*. Back pain
*. Blood in urine
*. Chills
*. Feeling of "impending doom"
*. Fever
*. Yellow skin ( jaundice )
EXAMINATIONS and TESTS
The health care provider will perform a physical exam. Blood
tests will usually show:
*. Bilirubin level is high
*. Complete/Full blood count (CBC) shows damage to red
blood cells or anemia
*. The patient's and donor's blood are not compatible
Urine tests show the presence of hemoglobin.(MEDICAL
LABORATORY ROLE)
TREATMENT.
Treatment may include:
*. Drugs used to treat allergic reactions (antihistamines)
*. Drugs used to treat swelling and allergies (steroids)
*. Fluids given through a vein (intravenously)
*. Medicines to raise blood pressure if it drops too low
PROGNOSIS.
ABO incompatibility can be a very serious problem that can
even result in death. With the right treatment, a full recovery is
likely.
Possible Complications
*. Kidney failure
*. Low blood pressure needing intensive care
*. Death
PREVENTION.
A medical laboratorian played a vital role in prevention of ABO
incompatibility. Careful collection and proper labeling of
donors and receipent blood. Careful testing of donor and
patient blood types before transfusion or transplant can
prevent this problem. (hoping that you will found this ABO
compatibility useful in your laboratory). Next issue of discurse
is Rhesus Incompatibity.
References
Goodnough L. Transfusion medicine. In: Goldman L, Schafer
AI, eds. Cecil Medicine . 24th ed. Philadelphia, Pa: Saunders
Elsevier; 2011:chap 180.