ID & Characterization of Blood & Bloodstain

ID & Characterization of Blood & Bloodstain

BEFORE DNA THERE WAS: SEROLOGY

Serology • examination & analysis of body fluids

Serology STAINS • often deteriorated and degraded

Serology • Correct steps must always be followed - PROTOCOL

Blood Facts The average adult has about FIVE liters of blood inside of their body, which makes up 7-8% of their body weight. Blood is living tissue that carries oxygen and nutrients to all parts of the body, and carries carbon dioxide and other waste products back to the lungs, kidneys and liver for disposal. It also fights against infection and helps heal wounds, so we can stay healthy. There are about one billion red blood cells in two to three drops of blood. For every 600 red blood cells, there are about 40 platelets and one white cell. http://www.bloodbankofalaska.org/about_blood/index.html

Presumptive testing Negative result • questioned stain is not likely blood Positive result • questioned stain is likely blood

Presumptive Screening Tests • Presumptive tests produce a color reaction or release of light • Tests rely on hemoglobin presence

Catalytic Color Test • Sample a stain with a clean, moist cotton swab • Add a drop of reagent • Add a drop of hydrogen peroxide • Color will develop immediately

Catalytic Color Test Examples: • Benzidine Alder – blue-dark blue • Phenolphtalein-Kastle-Mayer Test – pink • O-Tolidine test – blue • Leucomalchite Green (LNG) – green • Tetramethylbenzidine- Hemastix – green –blue green

CHEMILUMINESCENCE • light is emitted as a product of the chemical reaction

FLUORESCENCE • light is emitted when a substance is exposed to a shorter wavelength of light

Chemiluminescence & Fluorescence • More sensitive than color tests • May damage blood stain (no blood/DNA typing) Used to locate and define areas of blood • old blood stains • cleaned floor

LUMINOL • Method similar to color test • combined with oxidant and sprayed over area thought to contain blood • Emits a blue-white to yellow green glow • Extremely sensitive – 8 paint layers

FLUORESCEIN • combined with oxidant and sprayed over area thought to contain blood • Fluoresces when treated with a UV light • includes a thickener • makes it more effective on vertical surfaces • Study showed no interference with DNA analysis

Confirmatory test for Blood • Confirms presence of blood • Several test use crystal formation to detect hemoglobin 2 types of tests • Teichmann test • Takayama test

SPECIES ORIGIN • Most methods test for serum proteins • Serum proteins are found in all animals, but are slightly different • Species ID methods based on antigen/antibody interactions

Fish Blood Bird Blood Horse Blood Cat Blood Frog Blood Human Blood Snake Blood Dog Blood MicroscopicViews

GENETIC MARKERS IN BLOOD If a stain is blood, and it is human blood, then whose is it? • Blood Group Markers • Protein/Enzyme Markers • DNA

Blood Group Markers • ABO Markers • Lewis System • Rhesus System Many blood group markers, including:

Genetic Markers in Blood • Your blood group is genetically controlled and a lifelong characteristic Types of markers • Antigen Marker • Protein Marker • Enzyme Marker

BLOOD GROUP MARKERS ABO MARKERS • Look at antigens on Red Blood Cells • antigens are glycoproteins • are attached to outside of cell

Introduction to Blood ABO blood groups found on outside of cell

Blood Group Markers ABO Markers (antigen and antibodies) • person will have antibodies (A or B) to whatever blood group he/she doesn’t have • Otherwise, a persons blood would clump up and cause death

Blood Group Markers ABO Markers (antigen and antibodies)

BLOOD GROUP MARKERS ABO MARKERS • Testing is similar to species test • An anti-A, anti-B, or anti-AB antiserum (containing antibodies) is reacted with blood stain to detect blood cells • A, B, or AB blood cells are reacted with blood stain to detect antibodies

BLOOD GROUP MARKERS ABO MARKERS • Tests can get complicated with absorbing and releasing cells • Final step is usually testing for agglutination (blood clumping)

BLOOD GROUP MARKERS ABO MARKERS • A cells clump with anti-A • B cells clump with anti-B • AB cells clump with both • O cells do not clump

How common is your blood type?

Rh Factors • Scientists sometimes study Rhesusmonkeys to learn more about the human anatomy because there are certain similarities between the two species. While studying Rhesus monkeys, a certain blood protein was discovered. This protein is also present in the blood of some people. Other people, however, do not have the protein. • The presence of the protein, or lack of it, is referred to as the Rh (for Rhesus) factor. • If your blood does contain the protein, your blood is said to be Rh positive (Rh+). If your blood does not contain the protein, your blood is said to be Rh negative (Rh-). A+ A-B+ B-AB+ AB-O+ O- http://www.fi.edu/biosci/blood/rh.html

O A B AB Blood Transfusions A blood transfusion is a procedure in which blood is given to a patient through an intravenous (IV) line in one of the blood vessels. Blood transfusions are done to replace blood lost during surgery or a serious injury. A transfusion also may be done if a person’s body can't make blood properly because of an illness. Who can give you blood? People with TYPE O blood are called Universal Donors, because they can give blood to any blood type. People with TYPE AB blood are called Universal Recipients, because they can receive any blood type. Rh +  Can receive + or - Rh -  Can only receive - Universal Donor Universal Recipient

ID & Characterization of Blood & Bloodstain