Forensic Serology
Serology- is the term used to describe a broad
scope of laboratory tests which used to
specific antigen and serum antibody reactions.
-the term usually refers to the diagnostic
identification of antibodies in serum.
Blood
• Is been called the circulating tissue of the
body
• Referred to as highly complex mixture of cells,
enzymes proteins and inorganic substances.
• It is opaque.
Composition Of Blood
1. 45% Formed elements or Solid materials
consisting chiefly of cells
 Erythrocytes(RBC)- contains haemoglobin and
carry oxygen to the various cells in the body.
 Leukocytes(WBC)- are masses of nucleated
protoplasm. It defends the body from invading
microorganisms. It helps fight infection.
 Thrombocytes (BP)- cells that are produce by a
bone marrow and are necessary for proper
clotting of blood.
2. 55% Plasma- the fluid portion of the blood
where the cells are suspended. It is principally
composed of:
a. Water 90%
b. Solid(solutes) 10%
Albumen - The most abundant protein in the blood.
Globulins- has an important role in the immune mechanism of
the body. It carries drugs as well as sex and thyroid
hormones, lipids and iron.
Fibrinogen-the soluble precursor of fibrin, which forms blood
clot.
Plasma-the yellowish fluids of the blood in which numerous
blood corpuscles are suspended. A straw yellow liquid
formed when blood to which an oxalate has been added to
prevent clotting is allowed to stand.
Serum- a straw yellow liquid formed when clotted is allowed
to stand for sometime and blood contracts.
Blood fibrin
Blood serum
Importance of the Study of Blood
 As circumstantial or corroborative evidence against or
in favour to the perpetrator.
 As evidence in cases of disputed parentage.
 As an evidence in determination of the causes of
death and the length if victim survived the attack.
 As an evidence in the determination of the direction
of the case of victim or the assailant.
 As evidence in the determination of the origin of the
flow of the blood.
 As an evidence in the determination of the
approximate time the crime was committed.
Problems in the study of Blood
1. Where blood has to be searched?
2. Collection, preservation, packing and
transportation of specimen suspected to
contain blood.
3. Does the stain contain blood or another
substance?
BLOOD CHARACTERIZATION
Spot test- test for presence of blood.
a. Benzidine test- presumptive test for the presence of
blood.
b. Kastle Meyer test- using phenolphthalien and
hydrogen peroxide forming pink discoloration due
to the presence of peroxidase (enzyme) activity of
the blood haemoglobin.
c. Luminol Test- a spray reagent used to test for the
presence of blood even if it is not visible under
ordinary light. This is viewed using UV lamp.
d. Takayama test
e. Teichmann Test
Is the blood originated from a man or
an animal??
Test used for determination
1. precipitin Test- antigen and antibody
reaction forming precipitate.
2. gel diffusion – using agar test for human
blood.
3. Electrophoresis
The chronological test for Blood
1. Preliminary test-
2. Confirmatory test
3. Precipitin test
4. Blood grouping test
GATHERING AND SAFEKEEPING OF
EVIDENCE