Body Fluids : Body Fluids Forensic Serology
Blood : Blood A complex mixture of cells, enzymes, proteins & inorganic substances
Fluid portion of blood is called the plasma (55% of blood content)
primarily water
red cells (erythrocytes)
white cells (leukocytes)
platelets
What is Serology? : What is Serology? A term which describes laboratory tests which employ a specific antigen and serum antibody reactions
Erythrocytes : Erythrocytes Transport oxygen from the lungs to the body tissues
Transport carbon dioxide from the tissues to the lungs
Red cells possess chemical structures on their surfaces called antigens or agglutinogens
impart blood type characteristics
Blood Type : Blood Type Three types (alleles) of blood type gene
A, B, O
Each individual inherits one blood type gene from their mother & one from their father
6 possible combinations (genotypes)
AA, BB, OO, AB, AO, and BO
Genotype determines blood type
Antibodies or Agglutinins : Antibodies or Agglutinins Proteins that are present in the serum
responsible for ensuring that the only blood cells that can survive in a person are cells of the correct blood type
Slide 7 : Antibodies produced by the A alleles remove any red blood cells containing B antigens by clumping them together
Antibodies produced by the B alleles remove any red blood cells possessing A antigens
Slide 8 :
Type O Blood : Type O Blood Possessed by people whose genotype is OO
both parents passed on the O gene
have no antigens
these cells can be introduced into a person with Type A or Type B because these cells are not attacked by the antibodies these people possess
have both a & b antibodies
can only have other O type cells mixed with this blood
Type A : Type A Possessed by people with genotype
AA
AO
A is dominant to O
Possesses antibody b
will destroy any Type B red cells
compatible with A or O red cells
Type B : Type B Possessed by people with genotype
BB
BO
B is dominant to O
Possesses antibody a
will destroy any Type A red cells
compatible with B or O red cells
Type AB : Type AB Possessed by people with genotype
AB
A & B are co-dominant
Possesses no antibody
can have A, B, AB, or O cells added
Can’t be added to any other blood type without being destroyed by an antibody
Blood Typing : Blood Typing Blood typing is done by reacting whole blood with antibody A and antibody B
Blood Typing : Blood Typing
Slide 15 :
What is the universal donor? : What is the universal donor? Type O negative donors are known as universal donors because their blood may be transfused to patients of any other blood type in an emergency situation or if the specific needed blood type is unavailable. Because any patient can receive O negative blood, there is a constant need for O negative donors to give more often and shortages of type O blood can have critical consequences in national disasters. Whatever a person's blood type, they can be very important to someone in emergency crisis.
Relative Frequency of Blood Types in Human Populations : Relative Frequency of Blood Types in Human Populations
Rhesus Factor : Rhesus Factor Another characteristic of blood is Rhesus factor or Rh factor. It is named after the Rhesus monkey, in which the factor was first identified by Karl Landsteiner and Alexander S. Wiener. Someone either has or does not have the Rh factor on the surface of their red blood cells. This is indicated as + or -, and the two groups are described as Rh positive (Rh+) or Rh negative (Rh-), respectively. This is often combined with the ABO type. Type O+ blood is most common, though in some areas type A prevails, and there are other areas in which as many as 80 percent of the people are type B.
Slide 19 : Matching the Rhesus factor is very important, as mismatching (an Rh positive donor to an Rh negative recipient) may cause the production in the recipient of an antibody to the Rh(D) antigen, which could lead to subsequent hemolysis. This is of particular importance in females of or below childbearing age, where any subsequent pregnancy may be affected by the antibody produced. For one-off transfusions, particularly in older males, the use of Rh(D) positive blood in an Rh(D) negative individual (who has no atypical red cell antibodies) may be indicated if it is necessary to conserve Rh(D) negative stocks for more appropriate use. The converse is not true: Rh+ patients do not react to Rh- blood.
Slide 20 : Rh disease occurs when an Rh negative mother who has already had an Rh positive child (or an accidental Rh+ blood transfusion) carries another Rh positive child. After the first pregnancy, the mother develops IgG antibodies against Rh+ red blood cells, which can cross the placenta and hemolyse the red cells of the second child.
Rhesus Factor : Rhesus Factor
Slide 22 :
Slide 23 : Persons with Rh-positive blood can receive transfusions from donors with Rh-positive and Rh-negative blood.
Persons with Rh-negative blood can only receive transfusions from donors with Rh-negative blood.
Slide 24 : "Could a man with type B blood and a woman with type AB produce a child with type O blood?" I think not, because type O is recessive, and the B's seem to be dominant. My cousin thinks yes.
Slide 25 : What if the mother is type O+ and the father is A-? What would the offspring's blood type be?
The offspring could be:
A. A+, or O+
B. A-, or O-
C. A+, A-, O+, or O-
D. A+, or O-
Slide 26 : If the mother of a child is blood type O+ and the child is A-, what blood type would the father be? Does the Rh factor of the child being - mean that one of the parents has to be negative? Both of my parents are Rh - all of us siblings are Rh- as well. Could two Rh- parents give birth to a Rh+ child? and versi versa?
The father could be:
A. A+, A-, or O-
B. A+, A -, AB+, or AB-
C. B+, B-, or O-
Slide 27 : The father could be type A or type AB. The types that can be ruled out for the father are type O and type B. The father must be the source of the A allele of the child. The Rh factor information doens't discriminate potential fathers of the child. Even though the child is Rh-, it is not necessary that either parent be Rh-. The father of the child could be either Rh+ (heterozygous with one Rh+ allele and one Rh- allele) or Rh- (homozygous with two recessive Rh- alleles).
When the mother is Rh- and the father is Rh+ (heterozygous with one Rh+ allele and one Rh- allele), there is a 50% probability for an Rh+ child and a 50% probability for an Rh- child. When the mother is Rh- and the father is Rh-, as in the case of your own family, then all children (all of your siblings) will be Rh-.