Precipitin test identifies the
presence of proteins that are found only in human blood
. On the surface of red blood cells are molecules (proteins) called antigens. Antigens allow a living system to recognize foreign biological substances, such as infectious agents and allergens.
What is a precipitin test what is it used for?
Coccidioides precipitin is a blood test that
looks for infections due to a fungus called coccidioides
, which causes the disease coccidioidomycosis or valley fever.
What blood tests do forensic scientists use to test?
Blood detection
To detect blood at a crime scene or in the laboratory, an array of tests can be used. The most publicized test by crime shows is
the Luminol process
in which a chemical is sprayed onto a surface where blood is suspected to be.
How is serology used in forensic investigations?
The Forensic Serology Section is primarily responsible for
the detection and identification of biological material
(i.e., blood, semen, saliva, and urine) on physical evidence in order to: Link suspect(s) and victim(s) to each other and/or to the scene(s) Include or exclude potential suspect(s) or victim(s)
What could be determined from the test that Prof Paul uhlenhuth developed?
The Uhlenhuth test, also referred to as the antigen–antibody precipitin test for species, is a test which can
determine the species of a blood sample
. It was invented by Paul Uhlenhuth in 1901, based on the discovery that the blood of different species had one or more characteristic proteins.
What is antiserum used for?
Antiserum is human or nonhuman blood serum containing monoclonal or polyclonal antibodies that is used
to spread passive immunity to many diseases via blood donation
(plasmapheresis).
How do you take a precipitin test?
Precipitin Ring Test
To perform this test, a set of test tubes is
prepared by adding an antigen solution to the bottom of each tube
. Each tube receives the same volume of solution, and the concentration of antigens is constant (e.g., 1 mg/mL).
What methods do forensic scientists use?
- Chromatography, spectroscopy, hair and fiber analysis, and serology (such as DNA examination)
- Pathology, anthropology, odontology, toxicology, structural engineering, and examination of questionable documents.
What are the four types of presumptive tests?
Luminol, leuchomalachite green, phenolphthalein, Hemastix, Hemident, and Bluestar
are all used as presumptive tests for blood. In this study, the tests were subjected to dilute blood (from 1:10,000 to 1:10,000,000), many common household substance, and chemicals.
How do forensic scientists examine blood?
Analysts or investigators will typically
soak up pooled blood, or swab small samples of dried blood
in order to determine if it is human blood and then develop a DNA profile. This becomes critical when there are multiple victims.
What is the main job of a forensic serologist?
The job of a forensic serologist is
to analyze blood found at a crime scene and answer questions about it
. This may involve testing to ascertain whether the substance is blood and to determine whether it is human blood.
What is the first step in characterizing a bloodstain?
In order to characterize a bloodstain pattern, it is first necessary to macroscopically (with the unaided eye)
review the crime scene
. Typically, the point where the violence started will be close to the location where the least amount of blood is observed at the scene.
What is the phadebas test?
Phadebas is a
presumptive test used in forensic science examinations for the detection of areas of possible saliva staining
. The test is designed to react with amylase, a digestive enzyme present in saliva.
Can blood typing eliminate suspect?
Perhaps the most powerful application of blood evidence is
the ability to absolutely eliminate a person as a
potential suspect in a crime. Communication is the key to effectively processing blood evidence.
Is blood type Class evidence?
Class evidence consists of
substances such as blood and hair
, which can be used to place an individual in a general class but cannot be used to identify an individual. For example, blood typing can be used to establish whether someone has A, B, AB, or O blood, but cannot point to a person.
What type of evidence is blood typing?
Blood typing is
class evidence
because many people share the same blood type and this evidence is used to exclude a person as a suspect.
