This document discusses collection, packaging, and blood typing for forensic evidence analysis. It describes how to properly collect and store blood, semen, and saliva samples as evidence, including using dry or wet swabs. The document then explains how to analyze the samples, specifically focusing on blood typing methods like the Takayama and Teichmann tests to identify blood, and the process of ABO typing to determine blood groups. It also differentiates between secretors and non-secretors when analyzing bodily fluid samples for blood typing.
2. .
• SUBJECT- Advanced Biology And Serology.
• Subject code- FSS 755
• Faculty Name- Dr. Priyanka Verma
• Topic- Collection, packaging and Blood
typing
• Video lecture No.- 2
2/8/2023 2
3. Objectives
• To collect, preserve, and analyze
scientific evidence during the course of an
investigation.
• How does the blood sample as an evidence be
stored and examined.
• Differentiate secretors and non-secretors.
4. Learning outcomes
• They can understand the evidentiary value of
each evidence.
• After studying this module students shall be
able to know the typing methods of blood
group.
7. SALIVA AS AN EVIDENCE
SALIVA
Dry
Same as
blood
Wet
Same as
blood
Reference
Swab
Spit
Filter
paper
https://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=0ahUKEwju-ci5_4PYAhUG6iYKHWD-
CT4QjRwIBw&url=http%3A%2F%2Fwww.rehabcenter.net%2Fsaliva-mouth-swab-drug-detection%2F&psig=AOvVaw1YabW-
fMh3OlYe7h_0gWmr&ust=1513151638976794
8. How It Works
• They are used as a confirmatory test
– They detect whether or not a sample is/contains blood
and it not actually something like red paint or ketchup
– As opposed to a presumptive test which indicates the
POSSIBILITY that the substance being tested for is
present
9. Two Types of Tests
• The two tests that fall under the category of a
microcrystalline test are known as the
TAKAYAMA test and the TEICHMANN test
Takayama Crystals
11. Teichmann Test
• This test determines if there is blood present
on suspected dried blood stains.
• The hematin crystals begin to form when
heated blood is mixed with glacial acetic acid
where there is salt.
• The positive result is caused by the
combination of a halogen with
ferriprotoporphyrin (red-brown to blue-black
crystalline salt containing iron).
• This test produces pink crystals that can
reach up to 10 micrometers in size.
13. ABO Typing
– Human ABO locus
• Encodes galactosyltransferase
• Adds a second sugar group onto H antigen
• ABO gene has three alleles:
– O allele = null (non-functional)
– A allele = A-transferase (adds N-acetylgalactosamine to H
antigen)
– B allele = B-transferase (adds galactose to H antigen)
13
15. ABO Typing
• Secretors and non-secretors
– Almost everyone has a functional copy of FUT1
• ABO type expressed in blood
– 80% have functional copy of FUT2
• ABO type also expressed in other body tissues
– E.g semen, saliva
– 20% do not have a functional copy of FUT2
• Homozygous for a nonsense mutation in FUT2 resulting
in a truncated protein
• “Non-secretors”
15
16. ABO Typing
• Non-secretors caused problems in early
forensic serology
– ABO type could not be detected in semen or saliva
stains
– If semen or saliva stain tested “O”
• Assailant could be a non-secretor
– A, B, AB, or O blood type possible
• Assailant could be a Type O secretor
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17. FAQ’s
• What can you tell from blood test collected
from crime scene.
• How blood typing can be possible from dried
samples also.
• Solve the Case. The body of a 27 year old was found in a wooded picnic area.
Investigators searched the area and found what appeared to be a red substance near a picnic
bench. Hoping it was going to be helpful in the investigation, they sent a sample to a forensics
lab where they did a Takayama test. Results showed that no crystals appeared in microscopic
analysis, What was ruled out as part of the crime scene.