FORENSIC SCIENCE

PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids and their types

SUBJECT FORENSIC SCIENCE

Paper No. and Title Paper No. 12: Forensic Biology & Serology

Module No. and Title Module No. 4: Introduction of Biological Fluids and Their Types

Module Tag FSC_P12_M4

FORENSIC SCIENCE

PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

TABLE OF CONTENTS

Biological Fluids

Forensically important Biological fluids

Blood

Semen

Saliva

Urine

Vaginal Secretions

Feces

FORENSIC SCIENCE

PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

Learning Outcomes

After studying this module:

You should be able to identify various forensically important biological fluids.

You should develop an overview of a number of biological fluids commonly analyzed in

forensic science laboratories.

You should understand basic components of Blood, Semen, Saliva, Urine and other

forensically important biological fluids.

You should also be able to appreciate the use of these biological fluids in forensic casework.

Introduction – Biological Fluids and their types

Human body is largely composed of water. Life, as we see it, cannot become viable without water.

A large variety of fluids are secreted inside and outside of the body. They include more than 28

different fluids such as blood, semen, saliva, milk, tears, sweat, urine, etc.

List of biological fluid produced by the human body

• Amniotic fluid

• Aqueous humour and

vitreous humour

• Bile

• Blood serum

• Breast milk

• Cerebrospinal fluid

• Cerumen (earwax)

• Endolymph and

perilymph

• Exudates

• Feces

• Gastric juice

• Lymph

• Mucus

• Pericardial fluid

• Peritoneal fluid

• Pleural fluid

• Pus

• Rheum

• Saliva

• Sebum (skin oil)

• Semen

• Sputum

• Synovial fluid

• Tears

• Sweat

• Vaginal secretion

• Vomit

• Urine

FORENSIC SCIENCE

PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

Human body produces large variety of fluids

both inside and outside the body. Some of these

fluids are extensively used in the forensic

analysis to solve crime case.

The common biological fluid that a forensic

science lab examines include, blood, semen,

saliva, urine. In addition, the examination of

vaginal secretions and faeces is also conducted in

appropriate cases.

1. Blood

Blood is a fluid connective tissue in the body. It has several functions including transport of

molecules across the body, maintenance of body temperature, provide immunity to the

body, etc.

Blood is composed to two main component. Cellular part and Serum part as fluid part.

The cellular part further consists of Red Blood Cells (also known as erythrocytes), white

blood Cells & Platelets.

RBCs impart red color to blood due to the presence of iron containing protein haemoglobin

which transports oxygen and carbon dioxide. More precisely, RBCs enriched with oxygen

are red colored while RBCs devoid of oxygen are slightly purplish. This is the reason why

veins in the body appear bluish because they carry de-oxygenated blood.

FORENSIC SCIENCE

PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

1.1 Blood Cells

Blood cells can be characterized on the basis of the presence or absence of nucleus.

Mature RBCs and Platelets do not contain nucleus.

Platelets are important cells which are responsible for the clotting of blood.

WBCs, on the other hand, contain nucleus and mitochondria. WBCs contain DNA &

therefore enable a highly useful forensic DNA examination of blood samples.

Various cell types found in blood.

FORENSIC SCIENCE

PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

FORENSIC SCIENCE

PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

The process of blood clotting is described in detail in the above image. Platelets are

responsible for starting the clotting process which involves several factors and finally end

in the formation of fibrin polymer which appear as clot.

1.2 Blood groups

Red blood cells possess molecules

called antigens, on their surface.

In addition, antibodies are also present

in blood that recognize their

corresponding antigens. If a wrong

antigen is introduced in the body, it

will be recognized as a foreign

molecule by the antibodies present in

the body. This starts a process for

destroying that foreign antigen. This

process is known as immune response.

Since blood possess these antigen &

antibodies, it can easily be

characterized based on them

Thirty-three major blood group systems (including the AB and Rh systems) were

recognised by the International Society of Blood Transfusion (ISBT). Apart from the ABO

group, there are several other group systems such as Rh, Kell, Duffy, etc.

The most common grouping system is ABO system. ABO system was first discovered by

Karl Landsteiner.

In the A group blood, the RBCs possess A antigen. The plasma of A group blood possesses

Anti-B antibody.

FORENSIC SCIENCE

PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

List of blood group systems recognized by International Society of Blood Transfusion

(ISBT).

ISBT No System name System symbol Chromosome

001 ABO ABO 9

002 MNS MNS 4

003 P P 22

004 Rh (Rhesus) RH 1

005 Lutheran LU 19

006 Kell KEL 7

007 Lewis LE 19

008 Duffy FY 1

009 Kidd JK 18

010 Diego DI 17

011 Yt or Cartwright YT 7

012 XG XG X

013 Scianna SC 1

014 Dombrock DO 12

015 Colton CO 7

016 Landsteiner-Wiener LW 19

017 Chido/Rodgers CH\ 6

018 Hh/Bombay H 19

019 Kx XK X

020 Gerbich GE 2

021 Cromer CROM 1

022 Knops KN 1

023 Indian IN 11

024 Ok OK 19

025 Raph RAPH 11

026 JMH JMH 6

027 Ii I 6

028 Globoside GLOB 3

029 GIL GIL 9

030 Rh-associated glycoprotein RHAg 6

031 Forssman FORS 9

032 Junior JR 4

033 Langereis LAN 2

FORENSIC SCIENCE

PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

1.3 Blood as Forensic Evidence

Blood is one of the most significant evidence in

forensic casework.

Blood can establish the connection between a

victim and the criminal. Bloodstain pattern

analysis can reveal the mode of crime and

movement of criminal as well as the victim.

Blood Spatter is a technique to reconstruct the

event that led to the bloodstain. It includes

analysis of the shapes, locations and distribution

of blood stains

DNA analysis of blood sample can fix its origin to a single individual. Blood is also an

important evidence in toxicological analysis of various drugs and alcohol.

2. Semen Semen is a thick, yellowish white, glairy, opalescent,

secretion having a characteristic odor known as seminal

odor.

The fluorescence of the seminal stains is of a bluish white

colour.Semen Identification is useful as evidence in sexual

assault cases. It can prove that the sexual assault crime was

committed. It can also help identify the criminal.

Semen is composed of several components including

sperm cells, enzymes, sugars, minerals, organic chemicals

and vitamins.

Four glands contribute their secretions to the seminal fluid, viz., Testes, Seminal Vesicle,

Prostate and Bulbourethral gland. Bulbourethral gland is also known as Cowper’s gland.

The approximate percentage composition of semen is presented in this table indicating

contributions from various glands.

FORENSIC SCIENCE

PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

It is important to understand that sperm cells are produced only in the testes. Therefore, if

any person has received vasectomy, then his semen will not contain sperm cells. The other

component, however, would be present as usual.

Table showing percentage contribution of various gland secretions in seminal fluid.

2.1 Forensic Examination of Semen: An overview

As with other forensic exhibits, the investigation of semen is also carried out in a

methodical way using various tests.

First, the screening tests are performed in order to identify whether the questioned stain is

semen or not. Once the preliminary screening tests are positive, a more detailed

confirmatory analysis is carried out to establish that the stain is indeed semen.

Further exhaustive analysis of seminal stains is performed in order to individualize the stain

to a particular individual.

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PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

2.2 Finding Sperm cells in Semen

The identification of one or more sperms is a conclusive proof of the presence of

semen.

However, there are difficulties in the identification of sperms due to several reasons.

1. If a criminal is oligospermic, then his ejaculate may contain only a few sperms.

2. Another reason could be the condition of Aspermia where no sperms are

produced by the seminiferous tubules of the testes.

3. If the criminal has undergone Vasectomy which is the surgical procedure for

male sterilization to prevent sperm from entering into the seminal stream.

4. In addition to these, there may be other reasons such as sperms trapped in the

clothing not extracted into the testing extracts.

5. Disintegration of sperms can also take place during handling of the material,

etc.

Finding sperm cells in body cavities of a victim of sexual crime is the utmost priority

for obvious reasons. Several research findings indicate that motile and non-motile

sperms can be obtained at different duration in different body cavities. For example,

motile sperms can be obtained from the vaginal swabs of a victim within 6 to 28 hours

of the assault. However, non-motile sperms (which are devoid of flagella) can be

obtained for upto 10 days in vaginal cavity in certain cases.

FORENSIC SCIENCE

PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

The table below shows the approximate duration for which motile and non-motile

sperms can be found in the body cavities of a victim of sexual crime.

Maximum reported recovery times for spermatozoa collected from body cavities ¡n

living sexual assault victims

3. Saliva

Saliva is a fluid largely composed of water with

little amounts of electrolytes and enzymes. It is

secreted by a pair of salivary glands in the mouth.

Saliva is rich in the enzyme alpha-amylase (also

known as α-amylase, salivary amylase, or Ptyalin).

Ptyalin enzyme breaks down complex

carbohydrates into smaller sugar molecules.

Forensically, it is often seen in sexual assault

cases. Saliva tests can reveal certain disease

markers, viral infections, and the presence of

therapeutic as well as illicit drugs in the body.

Saliva samples can be analyzed from various types

of surfaces such as body parts, paper, envelopes,

cigarette butts, plastic and glass bottles, and metal

cans, etc.

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PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

3.1 Examination of Saliva

Saliva is an important evidence which can

provide useful information about the

personal contact of victim and

perpetrator.

The presence of saliva can be ascertained

by Starch-iodide and Phadebas tests.

Starch-iodide and Phadebas tests,

however, do not confirm the presence of

Human saliva. These are merely the test

for amylaze activity regardless of whether

that amylase has come from human or any

other source.

An advanced, monoclonal antibody based

test kit is used to identify human specific salivary

amylase. With RSID method, if a stain gives

positive reaction, then it is confirmed that human

saliva is present.

In addition, ABO group antigens can also be

detected in saliva, if the person is secretor. A secretor is an individual whose saliva and

other body fluids contain ABO antigens. Approximately 80% individuals are known to

be secretors.

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PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

Finally, since saliva may also contain buccal mucosa cells, it is possible to identify the

DNA profile of the person in question using advanced DNA profiling techniques.

4. Urine: Content and Identification Urine is an important biological liquid for forensic

analysis. A suspected urine stain may fluoresce

pale yellow or pale blue when viewed under long

and short wave UV light.

Characteristic odor of urine may be detected by

placing a small sample of the stain in a test tube

and heating slightly.

Urine contains two main constituents, namely,

Urea and Creatinine. Both these components are

tested for confirming the presence of urine. Urea

Nitrate Crystal test & Creatinine Test are

employed for such testing.

Urine is also an important exhibit for forensic

toxicology analysis. Almost all toxicants or their

metabolites can be analysed in urine samples using

various analytical procedures.

5. Vaginal Secretion & Faeces

Vaginal secretions contain a mixture of cells and liquid. Vaginal Secretions, appear

stiff on feeling when these are on clothing, under UV light examination, these show

fluorescence.

Vaginal secretion contain squamous epithelial cells that are rich in glycogen. This

enables them to be identified using Lugol’s iodine test.

FORENSIC SCIENCE

PAPER No.12: Forensic Biology & Serology

MODULE No.4: Introduction of Biological Fluids & Their Types

In addition to cells, vaginal secretion also contains acid phosphatase enzyme.

However, the acid phosphatase enzyme is much less as compared to the semen.

Therefore, it gives weak positive for acid phosphatase.

Faeces is a product of digestion. It is composed of

digested waste, undigested food, cells, organic

degradation products such as indole and skatole, etc.

In addition, faeces also contain Urobilinogen, which is

a colorless product of bilirubin reduction. About half

of the urobilinogen is excreted in faeces.

Urobilinogen is frequently tested in order to confirm the presence of faecal stains.

Forensically, vaginal secretions and faeces have limited use because of the difficulty in

analysis and lack of specificity in many forensic situations.

Summary:

1. Various Biological fluids produced by Human Body.

2. RBCs impart red color to blood due to the presence of iron containing protein

haemoglobin which transports oxygen and carbon dioxide.

3. Blood cells can be characterize on the basis of presence or absence of nucleus.

4. Red blood cells possess molecules called antigens, on their surface.In addition,

antibodies are also present in blood that recognize their corresponding antigens.

5. DNA analysis of blood sample can fix its origin to a single individual.

6. The fluorescence of the seminal stains is of a bluish white colour.

7. Saliva is rich in the enzyme alpha-amylase (also known as α-amylase, salivary

amylase, or Ptyalin).

8. A suspected urine stain may fluoresce pale yellow or pale blue when viewed under

long and short wave UV light.

9. Vaginal secretion contain squamous epithelial cells that are rich in glycogen.

10. Urobilinogen is frequently tested in order to confirm the presence of faecal stains.