SerologySerologyChapter 6Chapter 6

Three main questionsThree main questions

• Is this blood?Is this blood?

• Is this blood human?Is this blood human?

• What biochemical markers are found in the What biochemical markers are found in the blood?blood?

More than just IDMore than just ID

• Blood at a crime scene can be analyzed Blood at a crime scene can be analyzed byby• Composition of the bloodComposition of the blood• Patterns of blood samplePatterns of blood sample• Location of blood sampleLocation of blood sample

• To tell a significant amount of To tell a significant amount of informationinformation

Detection of BloodDetection of Blood

• Odor, color, and texture Odor, color, and texture are not enough to are not enough to detect human blooddetect human blood

• Dried blood lookDried blood look’’s s nothing like bloodnothing like blood

• Guaiacum test: plant Guaiacum test: plant extract turned blue extract turned blue when in contact of bloodwhen in contact of blood• Not reliableNot reliable• Human = animal bloodHuman = animal blood

Detection of BloodDetection of Blood

• Kastle-Meyer testKastle-Meyer test• Uses Uses

phenolphthalein phenolphthalein (indicator of acid)(indicator of acid)

• Mixed with H2O2 Mixed with H2O2 and blood, and blood, changes from changes from colorless to pinkcolorless to pink• False positivesFalse positives• Animal = Animal =

humanhuman

2 Stories of Blood 2 Stories of Blood DiscoveriesDiscoveries

• Louis Pasteur (1879)Louis Pasteur (1879)• discovered immunity to discovered immunity to

diseasesdiseases• Injected chickens with Injected chickens with

choleracholera• Chickens got sick, but Chickens got sick, but

recoveredrecovered• Never became infected Never became infected

againagain• Worked with anthrax and Worked with anthrax and

rabiesrabies

2 stories of blood 2 stories of blood discoveriesdiscoveries

• Edward Jenner Edward Jenner (1796)(1796)• Used cowpox Used cowpox

injections to injections to produce immunity produce immunity for smallpox for smallpox diseasedisease

• Came up with Came up with ““VaccinationVaccination”” from from the Latin name of the Latin name of the smallpox virus the smallpox virus (vaccinia)(vaccinia)

Detect HUMAN bloodDetect HUMAN blood

• Uhlenhuth Serum-based Uhlenhuth Serum-based test (1900)test (1900)• First test to identify First test to identify

HUMAN bloodHUMAN blood• Detection of specific Detection of specific

other species of other species of animal blood has animal blood has been since discoveredbeen since discovered

Check PointCheck Point

• How can we determine if How can we determine if the substance is blood?the substance is blood?

• How can we determine if How can we determine if the substance is Human the substance is Human blood?blood?

• Next question: how can Next question: how can we determine WHOwe determine WHO’’S S blood it is?blood it is?

• Guaiacum test & Guaiacum test & Kastle-Meyer testKastle-Meyer test

• Uhlenhutch Uhlenhutch serum-based testserum-based test

Did you know?Did you know?

• The adult human The adult human body contains 5.5 body contains 5.5 liters of blood. The liters of blood. The heart pumps nearly heart pumps nearly 300 liters every 300 liters every minute!minute!

WhoWho’’s blood it is?s blood it is?

• Discovery by Discovery by successful and successful and unsuccessful unsuccessful transfusions…transfusions…• In Medieval times, In Medieval times,

people would people would replenish blood replenish blood supply on humanssupply on humans

• Sometime person Sometime person died, sometime died, sometime livedlived

Fatal Transfusions?Fatal Transfusions?

• (1875) Observed that when human blood mixed, (1875) Observed that when human blood mixed, often clumping resulted…led to deathoften clumping resulted…led to death

• (1901) Karl Landsteiner discovered how to avoid this(1901) Karl Landsteiner discovered how to avoid this• Found ABO systemFound ABO system

How can Blood type be How can Blood type be determined?determined?

• Presence Presence or or absence absence of cell-of cell-surface surface proteinsproteins

• Anti-Anti-body body reaction reaction testtest

Composition of BloodComposition of Blood

• Blood = Tissue!Blood = Tissue!• Red blood cellsRed blood cells• White blood cellsWhite blood cells• PlateletsPlatelets

• Suspended in Suspended in plasmaplasma• Carries proteins: Carries proteins:

antibodies and antibodies and hormones, clotting hormones, clotting factors, nutrients, factors, nutrients, amino acids, salts, amino acids, salts, mineralsminerals

Composition of BloodComposition of Blood

• The most of our The most of our blood consists of blood consists of plasmaplasma, then the , then the red blood cells red blood cells follow. White follow. White blood cells makes blood cells makes up the least up the least amount of our amount of our bloodblood

Blood CellsBlood Cells

• Red blood cells Red blood cells (erthrocytes) carry (erthrocytes) carry oxygen and CO2oxygen and CO2• Hemoglobin Hemoglobin

contains iron contains iron which bind to O2 which bind to O2 in lungs and in lungs and carries it to cells carries it to cells in all tissues of in all tissues of the bodythe body

Blood CellsBlood Cells

• White blood cells White blood cells (leukocytes) fight (leukocytes) fight disease and disease and foreign invadersforeign invaders

• Platelets Platelets (thromocytes) aid (thromocytes) aid in blood clotting in blood clotting and repair of and repair of damaged blood damaged blood vesselsvessels

Immune SystemImmune System

• Our bodies can Our bodies can determine determine ““selfself”” and and ““non-selfnon-self”” particles particles

• Recognize viruses, Recognize viruses, bacteria, and bacteria, and parasitesparasites

• When found, white When found, white blood cells engulf blood cells engulf the particle and the particle and digest itdigest it

Immune ResponseImmune Response

• Antibodies are Antibodies are secreted from other secreted from other white blood cellswhite blood cells

• **White blood cells **White blood cells are the only blood are the only blood cell that has a cell that has a nucleusnucleus• Only blood cell that Only blood cell that

is a source for DNA is a source for DNA and used for DNA and used for DNA profilingprofiling

Immune ResponseImmune Response

History of DNA ProfilingHistory of DNA Profiling

• (1982)- white blood (1982)- white blood cells were first used cells were first used as a source of DNA as a source of DNA profilingprofiling

• Now- DNA profiling Now- DNA profiling and DNA and DNA fingerprintingfingerprinting

• Used in the Used in the Innocence Project to Innocence Project to help free inmateshelp free inmates

Blood TypingBlood Typing

• Checkpoint: Who was the Checkpoint: Who was the founder of the ABO blood founder of the ABO blood typing system?typing system?

• Karl Landsteiner (1900)Karl Landsteiner (1900)

• Is blood typing class evidence Is blood typing class evidence or individual evidence?or individual evidence?

• Class evidenceClass evidence

• Because many people share the Because many people share the same typesame type

Cell-Surface ProteinsCell-Surface Proteins

• The presence/absence of proteins within the The presence/absence of proteins within the cell or plasma membranes of red blood cells cell or plasma membranes of red blood cells determine blood typedetermine blood type

• An antibody reaction test is used to identify An antibody reaction test is used to identify each blood typeeach blood type

• Percentage in U.S. population of blood types:Percentage in U.S. population of blood types:

Type O Type A Type B Type AB

43% 42% 12% 3%

ABO System-Saves ABO System-Saves LivesLives

ABO SYSTEMABO SYSTEM

Rh FactorRh Factor

• Alex Weiner (1940) Alex Weiner (1940) worked with worked with Rhesus Rhesus monkeysmonkeys• Found another Found another

protein in red protein in red blood cellsblood cells

• 85% of human 85% of human population of this population of this proteinprotein• Rh+ (have Rh+ (have

protein)protein)• Rh- (no protein)Rh- (no protein)

Naming of Blood TypesNaming of Blood Types

• By what characteristic is the blood By what characteristic is the blood type of an individual determined?type of an individual determined?

• By the presence or absence of AB By the presence or absence of AB and Rh proteinsand Rh proteins

• Discovered through unsuccessful Discovered through unsuccessful blood transfusionsblood transfusions

• If received blood protein foreign to If received blood protein foreign to them- antibodies will cause blood them- antibodies will cause blood to clot…deadlyto clot…deadly

AntibodiesAntibodies

• B-lymphocytes B-lymphocytes secrete antibodies secrete antibodies

• Y-ShapedY-Shaped

• Bind to molecular Bind to molecular shape of an antigen shape of an antigen (foreign particle)(foreign particle)

• Binding site @ tip of Binding site @ tip of Y-shaped moleculeY-shaped molecule

Antigen-Antibody Antigen-Antibody responseresponse

• When a foreign invader is When a foreign invader is recognized by the immune recognized by the immune system…attack!system…attack!

• Antigen: viruses, bacteria, red Antigen: viruses, bacteria, red blood cell proteins for another blood cell proteins for another blood type (transfusion)blood type (transfusion)

1.1.B lymphocytes makes B lymphocytes makes specific specific antibodies against antibodies against that proteinthat protein

2.2.Phagocytes engulf the invaderPhagocytes engulf the invader

AgglutinationAgglutination

• CLUMPINGCLUMPING

• When each arm of Y shaped When each arm of Y shaped antibody attaches to red blood antibody attaches to red blood cellscells

• Make cease blood flowMake cease blood flow

• Why is this dangerous?Why is this dangerous?

• Red blood carries oxygen or Red blood carries oxygen or eliminates CO2… if body does eliminates CO2… if body does not get this, person will dienot get this, person will die

Check PointCheck Point

• What are the 4 components of blood?What are the 4 components of blood?

• Red blood cells, white blood cells, Red blood cells, white blood cells, platelets, and plasmaplatelets, and plasma

• What are the 4 types of blood?What are the 4 types of blood?

• O, A, B, ABO, A, B, AB

• What percentage of blood do each of What percentage of blood do each of the types account for in the U.S. the types account for in the U.S. population?population?

• 43%, 42%, 12%, 3% respectively43%, 42%, 12%, 3% respectively

Blood Transfusions

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

Microscopic Microscopic ViewsViews

Bird Blood

Cat Blood

Dog Blood

Fish Blood

Frog Blood

Snake BloodHuman Blood

Horse Blood

Blood Typing TestsBlood Typing Tests

• 3 separate tests 3 separate tests are performed!are performed!

1.1.Blood is mixed with Blood is mixed with antibodies that antibodies that bind to A proteinbind to A protein

2.2.Blood is mixed with Blood is mixed with antibodies that antibodies that bind to B proteinbind to B protein

3.3.Blood is tested Blood is tested with the Rh proteinwith the Rh protein

• What does it mean What does it mean if the blood clumps if the blood clumps with the first test?with the first test?

• Blood contains A Blood contains A proteins on cellsproteins on cells

• What does it mean What does it mean if the blood clumps if the blood clumps with the 2with the 2ndnd test? test?

• Blood contains B Blood contains B proteins on cellsproteins on cells

Presumptive vs Presumptive vs ConfirmatoryConfirmatory

• What did we conclude about our tests we What did we conclude about our tests we completed yesterday?completed yesterday?

• Recall the false positives that resulted Recall the false positives that resulted with testing horseradish…with testing horseradish…

• Did we have a definite detection of blood?Did we have a definite detection of blood?

Presumptive TestPresumptive Test

• We completed We completed presumptive tests…presumptive tests…

• This color test This color test indicated that a stain indicated that a stain was blood- but not was blood- but not what kind of bloodwhat kind of blood

• This test also gave a This test also gave a false positive result…false positive result…

Confirmatory TestConfirmatory Test• By the name…what would By the name…what would

you expect this test would you expect this test would result in?result in?

• Lack sensitivityLack sensitivity

• Large amount of the Large amount of the substance must be substance must be available for the test to be available for the test to be positivepositive

• Performed usually in a Performed usually in a laboratory- more equipment laboratory- more equipment and more controlledand more controlled

Presumptive vs Presumptive vs ConfirmatoryConfirmatory

• What would be your in distinction What would be your in distinction between these two test… discuss the between these two test… discuss the differences with your partnerdifferences with your partner

CompareCompare

Presumptive Confirmatory

Highly sensitive to but not specific for a particular substance

Lack sensitivity; They test positive for substance in question and ONLY that substance

Studies in serologyStudies in serology

• What materials do serologist study and analyze?What materials do serologist study and analyze?

• What are the body fluids possible to be studied?What are the body fluids possible to be studied?

Presumptive Tests for Presumptive Tests for BLOODBLOOD

• React with hemoglobinReact with hemoglobin

• Color reactors (clear to Color reactors (clear to pink)pink)

• Light @ wavelength Light @ wavelength emittedemitted

• Luminol Luminol (chemiiluminescence or (chemiiluminescence or fluorescence)fluorescence)

• phenolphthaleinphenolphthalein

Presumptive tests for Presumptive tests for bloodblood

• Luminol Luminol (chemical that (chemical that emitted light as a by emitted light as a by product of a reaction on product of a reaction on blood stains)blood stains)

• Fluorescein Fluorescein (emitted (emitted light as energy loss at a light as energy loss at a longer wavelength than it longer wavelength than it is illuminated with)is illuminated with)

• Must be viewed in the Must be viewed in the dark or with alternate light dark or with alternate light source (ALS)source (ALS)

• Photographic techniques Photographic techniques capture the imagescapture the images

• Emitted light is temporaryEmitted light is temporary

• Interfer with subsequent Interfer with subsequent testtest

Confirmatory Tests for Confirmatory Tests for bloodblood

• Use of crystal formation by heat Use of crystal formation by heat and chemicals- observed under and chemicals- observed under microscopemicroscope

• Takayama Takayama test (or test (or hemochromagen hemochromagen test)test)

• Procedure: Place sample of Procedure: Place sample of stain under coverslipstain under coverslip

• Heat while add pyradine in Heat while add pyradine in alkaline solutionalkaline solution

• Salmon colored crystals form if Salmon colored crystals form if blood presentblood present

• *Do you think labs do this test *Do you think labs do this test today?today?

• * Why/why not?* Why/why not?

Species OriginSpecies Origin

• Diffusion reaction testDiffusion reaction test

• OuchterlonyOuchterlony• Antibody-antigen Antibody-antigen

reactionreaction• Human blood & Human blood &

human antiserumhuman antiserum

• Process:Process:

SemenSemen

• Gelatinous mixture of Gelatinous mixture of cells, amino acids, cells, amino acids, sugars, salts, ions, and sugars, salts, ions, and other materialsother materials

• Spermatozoa = sperm Spermatozoa = sperm cellscells

• Volume of ejaculation Volume of ejaculation varies from 2 – 6 mL varies from 2 – 6 mL and contains and contains 100-150 100-150 million spermatozoamillion spermatozoa

Presumptive Tests for Presumptive Tests for SemenSemen

• Acid phosphatase AP in Acid phosphatase AP in semen is an enzymesemen is an enzyme

• Brentamine Fast Blue B Brentamine Fast Blue B (known carcinogen) (known carcinogen)

• Prepare paper or swabPrepare paper or swab

• Apply chemical- if turns Apply chemical- if turns purple (in 2 minutes), purple (in 2 minutes), positive for semenpositive for semen

• If sample is aged, neg If sample is aged, neg resultresult

• Positive result may occurPositive result may occur

Presumptive tests for Presumptive tests for semensemen

• Seen with ALS Seen with ALS (alternate light (alternate light source and amber source and amber goggles)goggles)

• Covers large areasCovers large areas

• Disadvantage- Disadvantage- some other fluids some other fluids may be highlighted may be highlighted (urine and saliva)(urine and saliva)

• Just because no Just because no light- canlight- can’’t assume t assume no semenno semen

Confirmatory tests for Confirmatory tests for semensemen

• Christmas tree stainChristmas tree stain• Tip of spermTip of sperm’’s head s head

turns pink, bottom turns pink, bottom of head dark red, of head dark red, middle portion blue, middle portion blue, tail yellowish-greentail yellowish-green

• Skin cells stain Skin cells stain green bluegreen blue

Confirmatory tests for Confirmatory tests for semensemen

• Time Since Intercourse (TSI)Time Since Intercourse (TSI)

• Motile sperm can survive in Motile sperm can survive in vagina for about 3 hours (1-vagina for about 3 hours (1-8 hrs)8 hrs)

• And up to several days in And up to several days in cervixcervix

• Intact sperm survive in Intact sperm survive in vagina up to 26 hoursvagina up to 26 hours• Heads- up to 3 daysHeads- up to 3 days

SalivaSaliva

• Where can saliva be found?Where can saliva be found?

• Bite marksBite marks

• Licked adhesivesLicked adhesives

• Eating and drinking surfacesEating and drinking surfaces

• Spitting (expectoration)Spitting (expectoration)

• DETECTION CAN BE TRICKYDETECTION CAN BE TRICKY

• Amylase! Amylase!

• Found in high Found in high quantities in quantities in saliva, but also saliva, but also in other body in other body fluidsfluids

• If presumptive If presumptive positive for positive for saliva, sent for saliva, sent for DNA analysisDNA analysis

UrineUrine

• What is urine?What is urine?

• Excreted fluid and waste Excreted fluid and waste products by kidneysproducts by kidneys

• Detect presence of Detect presence of ureaurea

• Or Or creatinecreatine

CheckpointCheckpoint

• Why would TSI be advantageous to Why would TSI be advantageous to investigate?investigate?

• What is the most common What is the most common presumptive test for semen?presumptive test for semen?

• Brentamine fast blue BBrentamine fast blue B

• What is the difference between a What is the difference between a presumptive and confirmatory test?presumptive and confirmatory test?

• List 3 presumptive tests for blood.List 3 presumptive tests for blood.

Additional Blood Additional Blood ProteinsProteins

Type Percent Fraction

MM 30% 30/100

MN 48% 48/100

NN 22% 22/100

• Other blood Other blood proteins exist…proteins exist…

• Inherited from our Inherited from our parentsparents

• The percentages of The percentages of these other these other proteins are:proteins are:

Blood-Type ProbabilityBlood-Type Probability

• Knowing the Knowing the frequency of frequency of different genes in a different genes in a population..population..• Determine Determine

probability/chance probability/chance that a blood type that a blood type will appearwill appear

Example ProblemExample Problem

• What percentage of the population would have A+ blood?What percentage of the population would have A+ blood?

• Type A blood = 42% of population & Rh+ = 85% of Type A blood = 42% of population & Rh+ = 85% of populationpopulation

• 1. Convert % to decimals1. Convert % to decimals• Type A = 0.42 of the populationType A = 0.42 of the population• Rh+ = .85 of populationRh+ = .85 of population

• 2. Multiple decimals2. Multiple decimals• 0.42 x 0.85 = 0.3570.42 x 0.85 = 0.357

• 3. Multiply by 100 to convert to %3. Multiply by 100 to convert to %• 0.357 x 100% = 35.7%0.357 x 100% = 35.7%

• ……about 36 out of every 100 people would have Type A+about 36 out of every 100 people would have Type A+

Why is Blood Type probability Why is Blood Type probability Helpful?Helpful?

• We can limit the size of our suspect population We can limit the size of our suspect population and help and help identify a suspectidentify a suspect

• If blood is found at crime scene with the following If blood is found at crime scene with the following proteins: Type A, N, Hp-1, Rh-, PGM-2proteins: Type A, N, Hp-1, Rh-, PGM-2• Probability = Probability = 1 in every 8600 1 in every 8600 people!people!• The more blood type proteins identified, The more blood type proteins identified,

uniqueness increasesuniqueness increases- number of people with - number of people with same combo as same combo as suspects decreasessuspects decreases

Blood EvidenceBlood Evidence

• Blood samples Blood samples – Can be analyzed to determine – Can be analyzed to determine blood blood type type andand DNA, DNA, which can be matched to possible which can be matched to possible suspects.suspects.

• Blood droplets Blood droplets – Can be analyzed to give clues to the – Can be analyzed to give clues to the location of a location of a crime, crime, movement of a movement of a victim, victim, and type of and type of weapon.weapon.

• Blood spatter Blood spatter – Can be analyzed to determine – Can be analyzed to determine patterns patterns that give investigators clues to how a crime that give investigators clues to how a crime mightmight have happened.have happened.

Is it Human Blood?Is it Human Blood?

• The method used is similar to The method used is similar to that we use when our bodies that we use when our bodies recognize and attack invading recognize and attack invading substancessubstances

• What two structures are What two structures are involved in our immune involved in our immune response?response?

• Antibodies and antigensAntibodies and antigens

• What does an antibody look What does an antibody look like? Draw it.like? Draw it.

ImmunoAssayImmunoAssay

• Also known as immunoprecipitation assayAlso known as immunoprecipitation assay

• What two words do you see in What two words do you see in immunoprecipitation?immunoprecipitation?

• Immune and precipitationImmune and precipitation

• Precipitin results when antibodies and antigens Precipitin results when antibodies and antigens interactinteract

Process for Process for immunoassayimmunoassay

• Antiserum is developedAntiserum is developed

• Recall how antiserum Recall how antiserum is produced for human is produced for human blood & share this with blood & share this with your neighboryour neighbor

• Imagine you are a Imagine you are a scientist needed to scientist needed to confirm the presence confirm the presence of bear blood. How of bear blood. How would you go about would you go about this detection?this detection?

PrecipitinPrecipitin

• An antibody which can An antibody which can precipitate out of a precipitate out of a solution upon antigen solution upon antigen bindingbinding

• We see a We see a foggy/murky/cloudy areafoggy/murky/cloudy area

• The precipitin forms The precipitin forms where matching where matching antibodies and antigens antibodies and antigens meetmeet

Precipitin TestPrecipitin TestSteps of the Precipitin TestSteps of the Precipitin Test

1.1.Once the antiserum or antibodies are createdOnce the antiserum or antibodies are created

2.2.They are applied to the unknown blood on a solid They are applied to the unknown blood on a solid substance (agar plate)substance (agar plate)

3.3.A preciptin line is formed between the antibodies A preciptin line is formed between the antibodies and antigens that matchand antigens that match1.1. A preciptin line is a region on the agar plate that A preciptin line is a region on the agar plate that

becomes cloudy or murky where the antigen and becomes cloudy or murky where the antigen and antibody meet and interactantibody meet and interact

PrecipitinPrecipitin

CheckpointCheckpoint

• What characteristic of a antibody What characteristic of a antibody allows it to identify a particular allows it to identify a particular antigen?antigen?

• Specificity!Specificity!

• Are immunoassay tests such as the Are immunoassay tests such as the immunoprecipitation assay an immunoprecipitation assay an example of presumptive or example of presumptive or confirmatory testing? Why?confirmatory testing? Why?

• Confirmatory… only will identify one Confirmatory… only will identify one specific antigenspecific antigen

SerologySerology

• A broad scope of laboratory A broad scope of laboratory tests that use specific tests that use specific antigen and serum antibody antigen and serum antibody reactionsreactions

• Serum: the yellowish liquid Serum: the yellowish liquid that separates from the that separates from the blood when a clot is formedblood when a clot is formed

Blood typingBlood typing

• OBJECTIVE: to determine OBJECTIVE: to determine the effect of the angle of the effect of the angle of impact and height on a impact and height on a blood dropblood drop

• DO NOW: DO NOW: • Make 3 observations Make 3 observations

about the first set of about the first set of blood drops; blood drops;

• Make 3 observations Make 3 observations about the second set of about the second set of blood dropsblood drops

VocabularyVocabulary

Blood SPATTER: Blood SPATTER: term that describes a stain that term that describes a stain that results from blood hitting a target results from blood hitting a target

Angle of Impact: Angle of Impact: angle created between the path angle created between the path the blood travels and the ground surface or floorthe blood travels and the ground surface or floor

SummarySummary

• Blood consists of cellular components and plasma Blood consists of cellular components and plasma containing dissolved ions, proteins and other moleculescontaining dissolved ions, proteins and other molecules

• Blood types result from the presence of proteins on the Blood types result from the presence of proteins on the surface of red blood cells and vary among individual surface of red blood cells and vary among individual humans. This variation can be used to exclude blood humans. This variation can be used to exclude blood samples from belonging to a group of individualssamples from belonging to a group of individuals

• Other proteins in the blood, such as enzymes, also Other proteins in the blood, such as enzymes, also show variation and can be used as class evidenceshow variation and can be used as class evidence

• Combinations of specific blood and enzyme types can Combinations of specific blood and enzyme types can narrow the possible source of a blood sample to a fairly narrow the possible source of a blood sample to a fairly small group of individualssmall group of individuals

SummarySummary• Blood splatter analysis can be used to recreate a crime Blood splatter analysis can be used to recreate a crime

scenescene

• The angle of impact is calculated as the arc sine = The angle of impact is calculated as the arc sine = width / lengthwidth / length

• The characteristics of blood drops on surfaces can The characteristics of blood drops on surfaces can show how the blood was deposited, at what rate the show how the blood was deposited, at what rate the blood was moving, the location of the origin or source blood was moving, the location of the origin or source of blood, and the direction on which the blood was of blood, and the direction on which the blood was moving when it struck the surfacemoving when it struck the surface

• Crime scene investigators used several tests to locate Crime scene investigators used several tests to locate and identify blood at a crime scene, including and identify blood at a crime scene, including visualization with Luminol and identification with the visualization with Luminol and identification with the Kastel-Meyer testKastel-Meyer test