Haemolytic disease of newborn (HDN)

•Is an alloimmune condition that develops in a fetus, 

 when the IgG molecules produced by the mother pass

 through the placenta

•This fetal disease ranges from mild to very severe,

 and fetal death from heart failure (hydrops fetalis) 

can occur

•Antibodies are produced when the body is exposed 

to foreign antigen 

•Some of the develeped antibodies can attack the body sistem
 and causing the reticulocytosis and eventually lead to anemia

•If present in the fetus, and may affect it in utero and 

persist after delivery 

•Rh disease is the most common form of severe HDN 

and it varies from mild to severe

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HOW TO DIAGNOSE

•The diagnosis of HDN is based on history and laboratory findings

•Blood tests done on the newborn baby

I.Biochemistry tests for jaundice

II.Peripheral blood morphology shows increase

reticulocytes. Erythroblasts (also known as 

nucleated red blood cells) occur in moderate and 

severe disease.

III.Positive direct Coombs test (might be negative 

after fetal interuterine blood transfusion)

•Blood tests done on the mother

                  Positive indirect Coombs tests

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Biochemistry Test for Jaundice

•Jaundice is yellow discolouration of skin, sclera, mucous
membranes, and other tissues due to excess of bilirubin in the
blood.

•Occurs when there is too much bilirubin circulating in the
blood.

*Bilirubin is a compound produced when hemoglobin is broken down in the blood.

1. Examination of feces 

•The stools are dark colored in hemolytic jaundice due to

excessive bile pigment, whereas it is pale and chalky white (clay

coloured) in obstructive jaundice due to absence of bile. 

2. Serum bilirubin

•The total, conjugated and unconjugated fractions can be

estimated. This helps in assessing the severity of jaundice 

and also in identifying the type. 

Vandenberg reaction 

is a qualitative test used in detecting the type of bile pigment in 

the serum.Direct positive test is given by conjugated bilirubin,

unconjugated bilirubin gives rise to the indirect reaction. When 
both pigments are present the reaction is biphasic.

Positive Direct Coomb Test

•The direct Coombs' test is used to detect antibodies that are 

already bound to the surface of red blood cells.

•These antibodies sometimes destroy red blood cells and cause

anemia.

Normal result:No clumping of cells (agglutination).

                         indicating that there are no antibodies to red         

                         blood cells.

* mother have anti-D antibodies baby blood will test for anemia and jaundice

•This may occur when there is a baby-mother Rh
incompatibility.


•The most common cause of hemolytic disease of the newborn is
an ABO incompatibility between mother and baby, especially 
with mothers that are blood group O.

Indirect Coomb's Test

•The indirect Coombs test finds certain antibodies that are in the
liquid part of the blood (serum).


•A test to determine whether a woman has Rh-positive or Rh
negative blood (Rh antibody titer) is done early in pregnancy. If
she is Rh-negative, steps can be taken to protect the baby.

Normal result

      

      A negative indirect Coombs test for Rh factor (Rh antibody titer) in a pregnant woman means that she has not developed antibodies against the Rh-positive blood of her baby.

     This means that Rh sensitization has not occurred.

Abnormal result

      

      If the Rh antibody titer test is positive in a woman who is pregnant or is planning to become pregnant, it means that she Rh sensitizationhas antibodies against Rh-positive blood