What is the second biomedical question investigators ask about blood?
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Is it human blood?
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What is the second biomedical question investigators ask about blood?
Is it human blood?
What is the population percentage of blood type O?
43%.
What is the purpose of blood group determination?
To identify blood types and prevent agglutination.
How is blood typing used in paternity testing?
It helps determine biological relationships.
What type of antibodies does the RSID™ saliva test use?
Dual monoclonal antibodies.
What happens to blood cells when mixed with Anti-A serum?
They clump together if the sample is type A.
What is a key aspect of bloodstain pattern analysis (BPA) at a crime scene?
Analyzing vertical drips and flow patterns.
What is the location of the ABO gene locus?
9q34.
What is the composition of blood platelets and white blood cells in total blood?
Less than 1%.
How many major phenotypes of PGM are there?
Three major phenotypes.
What is the population percentage of blood type A?
42%.
What type of bloodstains can precipitin tests be used on?
Dried and old bloodstains.
How many forms of blood can be used for analysis?
Two forms.
What is the third biomedical question investigators ask regarding blood?
Whose blood is it?
What are the two methods for ABO blood typing?
(i) ABO typing (ii) Reverse typing.
What does a color change within 1 minute indicate in preliminary tests for blood?
It indicates a positive reaction.
What information can bloodstain pattern analysis (BPA) reveal?
The origin of the blood stains, number of attacks, truthfulness of suspects and witnesses, type of instrument used, direction of impact, relative positions of individuals, and movements during the attack.
What is a disadvantage of preliminary tests for blood?
They can only indicate a likelihood that blood is present.
What is the primary test used to detect starch?
Starch - Iodine test.
How is serum separated from blood?
By allowing blood to clot and then separating the liquid that forms.
What does clumping with both Anti-A and Anti-B serums indicate?
The sample is type AB.
What chemical is contained in Hemastix strips that indicates blood?
TMB (C16H20N2).
What can mixing two different blood types lead to?
Blood agglutination.
What does RSID™ stand for in the context of saliva testing?
RSID™ is an immunochromatographic strip test.
What is the main target of the RSID™ saliva test?
Human salivary α-amylase.
What can produce a false positive result in blood tests?
Some vegetable materials such as potatoes and horseradish.
What is the purpose of microscopic identification in forensic analysis?
It serves as a confirmatory test for visual identification of sperm cells.
What percentage of total blood is plasma?
55%.
What reaction does Phosphoglucomutase (PGM) catalyze?
The reversible conversion of glucose 1-phosphate to glucose 6-phosphate.
What types of bloodstains can the Teichmann test be used on?
Dried and old bloodstains (over 20 years old).
What is the population percentage of blood type B?
12%.
What is a Punnett square?
A diagram used to predict the outcome of a particular cross or breeding experiment.
What does a positive result in blood tests indicate?
Not a positive proof of blood.
In which bodily fluids does Phosphoglucomutase (PGM) exist in significant concentrations?
In blood and semen.
What does BPA stand for?
Bloodstain Pattern Analysis.
What is the population percentage of blood type AB?
3%.
What is the role of blood typing in paternity testing?
It can help to exclude paternity but cannot absolutely verify it.
What type of molecules are found on the surface of human red blood cells?
Glyco-sphingolipids.
What is a key requirement for blood testing in precipitin tests?
Only a small amount of blood is required.
What are the major types of serological evidence?
Blood and body fluids generated by sexual assault cases, including semen, saliva, and vaginal secretions.
What is the purpose of incident reconstruction in forensic analysis?
To determine what happened during a crime.
What do Hemastix strips detect?
The peroxidase-like activity of hemoglobin.
What is saliva considered in forensic analysis?
One of the vital fluids secreted in human beings.
What indicates a blood sample is type B?
Clumping occurs when mixed with Anti-B serum.
What does 'negative' typically refer to in a general context?
A state or condition that is undesirable or unfavorable.
What enzyme digests starch into smaller carbohydrate units?
Amylase.
What can different components of blood be used for?
Different forensic assays.
What is applied to the gel medium in precipitin tests?
An electrical potential.
What can trigger a false positive in the Luminol test?
Other ions such as copper.
Why is blood commonly found in crime scenes?
Because it is often present during violent crimes.
What type of test is the PSA Semiquant?
An immunochromatographic rapid test.
What is the ultimate goal of forensic serology?
To determine who the blood or body fluids came from.
What environmental condition can lead to false positives in the Luminol test?
Enclosed spaces with excessive smoke.
What are the advantages of preliminary/presumptive tests for blood?
They are cheap, quick, reasonably sensitive, and convenient to use.
What is coagulated blood?
A mass of blood that has clotted, formed by the stimulation of fibrin.
What are polymorphic enzymes in human blood?
Enzymes that exist in several forms, such as Phosphoglucomutase (PGM).
What is the phenotype for a child with genotypes AA or AO?
Blood group A.
Which carbohydrate molecule is mentioned in relation to glyco-sphingolipids?
N-acetyl galactosamine.
What is the chemical formula for Leuco malachite green?
C23H26N2·H2O2.
What can interfere with preliminary blood tests?
Many other materials, including both oxidizing and reducing agents.
What is another carbohydrate molecule associated with glyco-sphingolipids?
Galactose.
What is the purpose of the Microcrystal Test?
To confirm the presence of blood.
What is the sensitivity level of the Luminol test?
It can detect bloodstains diluted to as little as 1 in 100,000.
What are the three main allelic forms of the ABO gene?
A, B, and O.
What is the first antibody used in the PSA detection process?
1st mouse Anti-human PSA antibody (gold-labelled; mobile).
What is a limitation of the amylase activity-based tests?
They are not specific to humans.
What are two limitations of preliminary tests for blood?
Sensitivity and not being definite proof.
What technique is used to analyze PGM patterns?
Electrophoresis.
What is blood?
The fluid that circulates in the principal vascular system of human beings and other vertebrates.
What does forensic serology involve?
The examination and analysis of body fluids.
Which enzyme can catalyze the oxidation of luminol?
Horseradish peroxidase.
What is the purpose of the PSA Semiquant test?
To detect PSA levels.
What are the possible genotypes for a child with blood group A?
AA and AO.
What is meant by blood being projected from the body?
Blood leaves the body due to a person or object applying some force other than gravity.
How can BPA help in understanding the crime scene?
By revealing the locations and movements of the victim and attackers during the attack.
What can a negative result in blood tests conclude?
The absence of detectable quantities of heme.
What happens to blood cells when mixed with incompatible blood types?
They clump together.
Why is bloodstain pattern analysis considered important?
It provides critical insights into the dynamics of a crime scene.
What is an example of a Microcrystal Test?
Takayama test.
How is the Luminol reagent applied during testing?
It is sprayed onto a suspect item.
What are Takayama crystals?
Crystals formed during the Takayama test that indicate the presence of blood.
What role does iron in hemoglobin play in the Luminol test?
It acts as a catalyst in the reaction.
What is mixed with blood samples for ABO typing?
Serums containing antibodies for Type A and B blood.
How can human blood be identified using the precipitin ring test?
By using rabbit antibodies against human blood antigens.
What is a key advantage of the KM color test regarding the sample?
It is not destructive to the sample, allowing for further tests.
What color change indicates a positive result in the KM color test?
Colorless to pink.
From where can swabs be taken to detect vaginal secretions?
From a suspect’s penis or any suspected foreign objects.
What is a limitation of the Acid Phosphatase test?
Certain materials like watermelon or cauliflower juice can cause false positives.
What is the first biomedical question investigators ask regarding blood?
Is it blood?
What can bloodstains indicate about a crime?
They can provide clues about the locations of the victim and suspect during the crime.
What information can blood reveal in forensic analysis?
The presence of disease, drugs, and alcohol.
What is a new feature mentioned for the PSA test?
New cassette.
What does LMG stand for in forensic testing?
Leuco malachite green.
What is the primary use of Hemastix strips?
To detect blood in urine.
Why is saliva important for individual identification?
It is an important source of DNA.
Where is α-amylase found in higher concentrations?
In saliva, 50 times higher than in other body fluids.
What does 'positive' typically refer to in a general context?
A state or condition that is desirable or favorable.
What is the basis of the LMG test?
The peroxidase-like activity of hemoglobin.
What controls the A - B - O genotype?
Multiple alleles.
What is un-coagulated blood?
The fluid portion of un-clotted blood.
What is the sensitivity of the KM color test?
1 in 10,000.
What does the Phadebas amylase test indicate?
The presence of amylase, indicated by a blue color change.
What substances does plasma contain?
Proteins, antibodies, hormones, vitamins, and salts.
What is required to prepare a reagent for the precipitin ring test for human blood?
Antiserum against human blood.
What process is used to separate components of blood?
Centrifugation.
In which demographic are glycogen-rich vaginal epithelial cells absent?
In young girls who have not started menstruating.
What can cause false positives in the Acid Phosphatase test?
Some fungi and certain food juices.
What does PSA stand for?
Prostate-Specific Antigen.
What are the two main categories of how blood can leave the body?
What causes passive bleeding?
The action of gravity.
Who developed the Teichmann test?
Ludwik Teichmann in 1853.
How can blood be used to identify individuals in forensic cases?
Through DNA analysis.
What is a key characteristic of the RSID™ saliva test?
High specificity.
How sensitive is the Teichmann test compared to color tests?
It is less sensitive than color tests such as the luminol test.
What happens when antibodies and antigens diffuse toward one another on an agar-coated plate?
A line of precipitation forms where they meet if the blood is from a human.
From where can saliva be recovered?
From stamps, food, and bite marks.
What is used as a control in the immunodiffusion assay?
Human blood.
What activity is tested to determine the presence of saliva?
α-amylase activity.
What is the purpose of the precipitin ring test?
To identify the species of blood.
How can 'positive' be perceived in emotional contexts?
As feelings of happiness, optimism, or enthusiasm.
What is the main component of plasma?
Mainly water.
What color indicates the presence of starch in the Starch Iodine test?
Blue.
What principle is used in the PSA detection method?
Semiquantitative principle.
What do confirmatory tests for blood rely on?
A reaction between a chemical and the hemoglobin molecule in red blood cells (RBC).
At what temperature and duration is the amylase solution incubated?
37°C for 6 hours.
How does the concentration of Acid Phosphatase in seminal fluid compare to other body fluids?
It is much higher in seminal fluid.
What is one importance of blood typing in investigations?
It helps narrow down investigations.
What does serum contain?
Water, antibodies, proteins, salts, and many other components.
What is an example of a stain used in microscopic identification?
Christmas Tree stain.
What color does the LMG test produce?
Colorless to blue-green.
What is a limitation of preliminary blood tests regarding species?
They cannot differentiate between species.
What percentage of total blood do red blood cells constitute?
45%.
How can 'negative' be perceived in emotional contexts?
As feelings of sadness, anger, or pessimism.
What is the sensitivity range of the LMG test?
1 in 5,000 to 10,000.
What is an allele?
Alternative forms of a gene located at the same point on a particular pair of chromosomes.
What type of cells are detected in vaginal secretions?
Glycogen-rich epithelial cells.
What is the result of the starch-iodine test when amylase is present?
Yellow/brown color indicating glucose and free iodine.
What is the purpose of mixing serum with blood in reverse typing?
To determine the blood type of the sample.
How are A and B alleles related?
They are codominant.
What is the electrophoretic PSA test used for?
It is used as a confirmatory test for the presence of PSA.
What color indicates a positive result in the Acid Phosphatase test?
Purple (using Fast Blue B Dye).
What are glyco-sphingolipids composed of?
A hybrid molecule of carbohydrate and lipid.
What is a limitation of the Teichmann test?
It can't determine the species from which the blood originated.
What is the purpose of using a Phadebas tablet in testing?
To measure amylase activity.
How do you use Hemastix strips?
Moist the strip with DI water and place it in contact with the bloodstain.
What color represents the anterior part of sperm when stained with Christmas Tree stain?
Pink.
What indicates that a sample is type B when mixed with type A blood?
Clumping occurs.
What is Phadebas?
A synthetic biochemical substrate consisting of starch polymers with a blue dye covalently bonded.
What color change indicates the presence of blood when using Hemastix strips?
Colorless to green.
What is the main source of PSA?
It is mainly found in semen, secreted by the prostate gland.
What types of antiserums are commercially available for species identification?
Antiserums against different animals such as dog and cat.
What does a negative result indicate in the PSA test?
No PSA in the sample.
What is the result of the Phadebas test when glucose is produced?
Colorless solution.
What is a key advantage of the Phadebas test?
No special apparatus is required, allowing it to be used at the scene.
When are glycogen levels in vaginal epithelial cells typically high?
Around ovulation.
In which demographic are glycogen-rich vaginal epithelial cells uncommon?
In postmenopausal women.
At what wavelength is the glucose measured in the Phadebas test?
620 nm.
What type of blood is collected without an anti-coagulant?
Coagulated blood.
What does it mean if there is no clumping with either serum?
The sample is type O.
What methods can be used to settle blood?
By gravity or centrifugation.
Why is the determination of vaginal secretions important?
It is crucial in cases involving sexual assault.
Why are preliminary tests for blood not sufficient?
They are not specific and can give false positive results.
In terms of feedback, what does 'negative feedback' imply?
Criticism or suggestions for improvement.
How does the concentration of PSA in vaginal fluid compare to that in semen?
In vaginal fluid, it is much lower, at 0 - 1.25 ng/ml.
What is the significance of the PSA test in forensic analysis?
It serves as a confirmatory test for a positive AP test sample.
How stable is PSA in terms of recovery from old semen stains?
PSA could be recovered from 30-year-old semen stains at detectable concentrations.
What does a clear area in the gel indicate?
No starch is present due to digestion by amylase.
What can cause a false negative result in blood tests?
The presence of a reducing agent that interferes with the oxidation reaction of the tests.
What are the three main allelic forms of blood type?
A, B, and O.
What does PSA stand for in the context of confirmatory tests?
Prostate Specific Antigen.
What indicates that a sample is type A when mixed with type B blood?
Clumping occurs.
Where is amylase found in the human body?
In both saliva and the pancreas.
What does it mean if there is no clumping when mixing blood?
The sample is type AB.
What are some limitations of microscopic identification?
Old samples and vasectomized males.
When was the Takayama test developed?
In 1912 by Takayama L.
What bond does the B allele form?
Joins D-galactose to D-galactose.
What is the characteristic of the O allele?
Contains a deletion that results in a loss of enzymatic activity.
What is the control solution used in the experiment?
Saliva amylase solution.
What is the Kastle-Meyer (KM) color test used for?
To detect the presence of blood.
What is the minimum amount of blood that can be detected using the Teichmann test?
Down to 1 μl of blood or 0.1 mg of hemoglobin.
What property of blood hemoglobin is utilized in the KM color test?
It possesses peroxidase-like activity.
What are the two formats of the Phadebas test?
Starch - Blue dye and Amylase - Blue dye.
What is formed when amylose interacts with iodine?
A dark blue/black color due to the formation of helices.
What type of serum is mixed with known type A and B blood to determine type O?
A serum sample containing antibodies.
In terms of feedback, what does 'positive feedback' imply?
Praise or reinforcement of good performance.
Is the test for detecting vaginal secretions conclusive?
No, it is not conclusive due to variability in glycogen levels.
Why are KM color tests typically preferred in forensic analysis?
They are cheaper and faster.
How is the amount of amylase quantified in the experiment?
By measuring the size of the clear area (cm²).
What color does the starch-iodine complex turn when iodine is present?
Dark blue/black.
What is the role of the second antibody in the PSA detection process?
2nd mouse Anti-human PSA antibody (membrane fixed).
What is the stability duration for detecting α-amylase activity?
Up to 28 months.
What test is used to visualize starch digestion?
Radial Gel Diffusion Starch Iodine test.
What is the concentration range of PSA in semen?
0.2 - 3 mg/ml.
What does the B allele encode?
1-3-galactosyltransferase.
What happens to starch when it forms a complex with iodine?
It produces a blue color.
What is the purpose of measuring the size of clear areas in the test?
To determine the relative amount of amylase in the samples.
What type of cases usually involve testing for seminal stains?
Sexual assault cases.
What color represents the posterior part of sperm when stained with Christmas Tree stain?
Dark red.
What does the A allele encode?
1-3-N-acetylgalactosamine transferase.
What type of blood sample is used for ABO typing?
Uncoagulated blood.
What bond does the A allele form?
Bonds N-acetylgalactosamine to D-galactose.
What chemical reaction occurs in the Luminol test?
H2O2 + luminol produces a strong glow.
Which reagent is used to stain glycogen in vaginal secretions?
Periodic acid-Schiff (PAS) reagent.
What is used to prevent blood from coagulating?
Anti-coagulants like EDTA, heparin, and citrate.
How can antibodies against human blood be produced?
By injecting human blood into a rabbit or other animals.
What is the Acid Phosphatase (AP) Test used for?
It is a presumptive test for seminal stains.
What reagents are required for the immunodiffusion assay?
Antiserum against human blood and an agar-coated plate with wells.
What does a positive result indicate in the PSA test?
Presence of PSA in the sample.
What does the blue dye in the Phadebas test indicate?
It is released at a rate proportional to the quantity of the enzyme present.
What type of test is the KM color test considered?
A preliminary/presumptive test for blood.
What is a recessive allele?
An allele that produces its characteristic phenotype only when paired with an identical allele (e.g., O).
What is the significance of diffusion in the PSA test?
It allows the antibodies to interact with the PSA in the sample.
What substrate is used in the Acid Phosphatase test?
α-naphthyl phosphate.
What color represents the neck and tail of sperm when stained with Christmas Tree stain?
Green.
What type of antiserum is used in the immunodiffusion assay?
Rabbit antiserum against human blood.
What is a dominant allele?
An allele that produces the same phenotype whether paired with an identical or different allele (e.g., A, B over O).
What types of bloodstains can the Luminol test detect?
Blood stains that have been washed out, wiped off, or are invisible to the naked eye.
Does the Luminol test interfere with subsequent DNA testing?
No, it does not interfere.
What is the second most often seen body fluid in forensic cases?
Seminal fluid/semen.
What enzyme is secreted by the prostate gland into seminal fluid?
Acid Phosphatase (AP).
