Bodily fluids Flashcards
Which of the bodily fluids is the most common and the most useful?
Blood
To gain more information, we can do/analyze these 4 things to blood.
biological and chemical tests.
blood stains and splatter
coagulation.
What is the name of the specialist who analyzes blood?
Serologist
What can we find in the plasma?
- White blood cell (leucocytes)
- Red blood cells (erythrocyte)
- platelets
What can we find to identify with the red blood cells and serum?
blood type
In red blood cells, we find ____ and _____ that can tell us the blood type.
antigens
antibody
Mixing blood tyes can lead to ___.
death
Blood group A: \_\_ antigens (round). \_\_\_ antibodies (spiky) strong negative reaction to type \_\_\_.
A
B
B
Blood group B: \_\_ antigens (spiky). \_\_\_ antibodies (round) strong negative reaction to type \_\_\_.
B
A
A
Blood type AB:
__ antigens .
___ antibodies
strong negative reaction to type ___.
A and B
No
none
Blood type O:
__ antigens.
___ antibodies
strong negative reaction to type ___.
no
A and B
A and B
What happens when A type blood meets Anti-A serum?
agglutination
What happens when B-type blood meets Anti-B serum?
agglutination
What happens when AB-type blood meets Anti-B serum?
agglutination
What happens when AB-type blood meets Anti-A serum?
agglutination
What happens when type-blood O meets any antiserum?
nothing
What does Rh stand for?
Rhesus factor
Rh+ has __ antigens. Does it have Rh antibodies?
Rh
no
Rh+ can receive blood from?
Rh - and Rh +
Rh -:
antigens?
antibodies?
No Rh antigens
Rh antibodies are not naturally present, they develop when they receive blood for the first time. 1st time receiving = okay, the second time? death
___% are Rh+ so ___% are Rh-
___% are O and ___% are A
___% are B
___% are AB
85 - 15
45 - 40
11 - 4
In which cases are paternity tests used?
Child support and custody, kidnapping, insurance fraud and inheritance conflicts.
In depth paternity testing requires ____. But we can use ___ for preliminary testing.
DNA analysis
blood-typing
What is the genotype and the phenotype?
Genotype= in your gene (2 letters) Phetnotype= how genes affect you (1 letter)
The phenotype can be determined by _____, but genotype requires _____.
blood test
DNA analysis
Why would we blood test someone if cant identify precisely?
Include or exclude possible fathers.
What is the name of the grid used to determine possible genotypes?
Punet square
What is the certainty of DNA analysis?
99%
Name other tests that can replace DNA and why we don’t really use them?
HLA, Haptoglobin
not as certain as DNA
Blood at the crime scene can look like a ___ paint splotch or _____ grease stain, depending on ______.
purple
brown
age of the stain
What are the 3 questions crime scene investigators ask when confronted with a stain?
1- Is it blood?
2- Is it human blood?
3- Whose blood is it?
What are the limits of blood testing?
not enough blood
degradation by chemicals
putrefaction often alters evidence in hot/humid conditions.
What are the 2 categories of presumptive tests in blood testing?
colour tests and fluorescent tests
What is the name of the test that takes 1-2 minutes.
Creates a dark pink colour in presence of blood. What does this liquid also react with?
Kastle-Meyer
Potatoes and horseradish
What is the name of the test that creates a blue-green colour in the presence of blood?
tetramethylbenzidine (TMB)
What is the name of the test that creates a green colour in the presence of blood?
Leucomalachite green (LMG)
_____ tests are extremely sensitve (_____ million). It can expose blood that has been ____ (except with ____) and ____ over.
Luminol 1/10 cleaned chlorine bleach painted
___ tests can be used when the surface has been cleaned with _______. Also it ____ less than the Lumino tests.
Fluorescein
chlorine bleach
drips
What is the name of the only confirmatory tests for blood?
- It creates _____ because of the reaction between chemicals and _______ from the RBC.
- Works well with ___ stains.
Teichmann and Takayama
crystals
hemoglobin
older
What technique is used to know if the blood found is human blood?
Create an antibody in animals that will react to human blood. Thus, if precipitation when we mix it we know it is human blood.
Whose blood is it?
1- Serologists identify _____ of the sample.
2- Other similar tests such as ______, or _______.
3- _____ analysis.
blood-type
phosphoglucomutase (PMG)
adenylate Kinase
DNA
Where is semen usually found on a crime scene?
In the corpse or victim, underwear, condom, bed sheets, mattress, flooring and carpeting.
What are the two presumptive tests for semen?
1- Acid phosphate enzymes
false positive with fruit and vegetables, fungi, contraceptive cream and vaginal fluids
2- spermine and choline
forms a crystal
WHat are the two confirmatory tests for sperm?
1- microscopic analysis for spermatozoa
2- prostate-specific antigen
highly concentrated in semen even after a vasectomy
How can semen help us know the time of the intercourse?
depending on the movement of the sperm.
- moves for 4-6 hours in living victims
- up to two weeks in a corpse
How can the secretor status help us eliminate suspects with sperm, saliva and tears?
Secretors (80-85%) of the population secrete AOB blood types.
Where is saliva found? What are the presumptive tests and confirmatory tests? What about DNA in saliva?
Bite marks, stamps to food.
test for alpha-amylase (an enzyme used to break down carbohydrates).
No confirmatory tests
can yield DNA
Vaginal fluid can be important in ______ and ____ rapes.
non-ejaculatory rapes and object rapes
What is the presumptive test for vaginal fluids? Explain why it often gives false negative?
Periodic Acid-Schiff (PAS)
A reagent that stains glycogen (found in vaginal epithelial cells)- stains magenta
young girls and post-menopausal women.
