Abo Blood Groups 126f47

Objectives…  To:

1.Name the blood groups of ABO and Rh system. 2.Give the principle of determination of blood groups. 3.Study the effect of Rhesus factor in the case of Erythroblastosis Fetalis. 4.Determine blood groups by using antisera. 5.Give the importance of cross-matching. 6.Describe the importance of blood groups determination in the process of blood transfusion.

What does blood types mean? Different blood types have different SURFACE PROTEINS on RBCs

ABO System… Antibodies (agglutinins ) in plasma are considered naturally occurring; that is produced without any known exposure to Antigen. Agglutinins are gamma globulins, as are almost all antibodies, produced by bone marrow and lymph gland cells .

Agglutination process in Transfusion Reactions  If a person istered blood of incompatible type

so that anti-A or anti-B plasma agglutinins are mixed with red blood cells that contain A or B agglutinogens.  This causes the cells to clump, which is the process of

"agglutination."

Agglutination

Rh Factor If your blood does contain the Rh protein, your blood is said to be Rh positive (Rh+) If your blood does NOT contain the Rh protein, your blood is said to be Rh negaitive (Rh-)

Blood Transfusion Indications of blood transfusion:1. 2. 3. 4.

Loss of blood. Blood disease. Severe Anaemia. Erythroblastosis foetalis.

Precautions Of Blood transfusion:•Blood Typing. •Major Cross Matching. •Hb content of transfused blood is not <90%. •Free from infectious diseases. •Fresh non frozen blood <21days storage, stored at 4ºC.

Cross matching: This is done by performing the following two tests:

Test

Donor

Recipient

1

RBCs + Plasma

(Major Cross Match)

2

Plasma + RBCs

(Minor Cross Match)

no agglutination means the blood samples are compatible and blood transfusion can be made safely.

Complications Of Incompatible Blood Transfusion Blockage of blood capillaries caused by agglutination RBCs  t pain and anginal pain. Haemolysis, which leads to:

1. Release of histamine →↓ABP→ shock. 2. Release of K→ hyperkalamia. 3. Release of Hb →bilirubin →jaundice. 4. Release of Hb→ precipitation of Hb as hematin crystals in renal tubules blocking them. 5. 1 & 4 can lead to Acute renal failure.

Rh factor is of particular medical important

Erythroblastosis fetalis Prevention When Rh-ve female delivers Rh+ve foetus, anti- D antibodies are given to her immediately after delivery to neutralize D antigen of the Rh foetal cells to prevent sensitization of the mother. Treatment Replacement of the blood of the baby with Rh-ve O blood. (Exchange transfusion)

Procedure: Divide a clean glass slide into three equal divisions using a glass marking pencil, then label these divisions anti-A, anti-D and anti-B respectively.

A

D

B

Place a drop of anti-A serum, anti-D serum, and anti-B respective divisions.

A

B

serum

D

in

the

Prick a finger with a sterile lancet, and add one drop of blood to each anti-serum. With the help of a clean wood stick, mix the blood & anti-sera thoroughly. Use separate wood sticks for separate sera.

A

D

B

- Clumped red cells give a coarse reddish granular appearance.

- Microscopic examination may be carried out for the confirmation of agglutination.

Examples…