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Serology

Serology. Allie Wheeler, Amber Conrad, Aleisha Murrell, Harsha Pinnamaraju , Orin Sparks, Jonathan Huynh, Kyle Eberle. Table of Contents. Introduction…1 Objectives and Goals…2 Educational Requirements…3 Analytical Procedure…4 Presumptive Test…5 Blood Typing…8

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Serology

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  1. Serology Allie Wheeler, Amber Conrad, Aleisha Murrell, HarshaPinnamaraju, Orin Sparks, Jonathan Huynh, Kyle Eberle

  2. Table of Contents • Introduction…1 • Objectives and Goals…2 • Educational Requirements…3 • Analytical Procedure…4 • Presumptive Test…5 • Blood Typing…8 • Interpreting Blood Stain Patterns…12 • Crime Scene Reconstruction…16 • Glossary…23

  3. Introduction • The following information presented is to help understand serology, the study of blood, in forensic science. Blood is the most common piece of evidence found at a crime scene and is key to solving any crime. The following information is presented: • Blood Typing • Blood Spatter • Crime Scene Reconstruction • Educational Requirements to be an Expert in this Field • And much more! AW

  4. Objective and Goals • Forensic Serology is dedicated to providing forensic analysis of physical evidence to the criminal justice system. • Specialists analyze evidence, usually associated with blood, to identify any suspects. • Tests and analysis are performed in controlled environment using proper procedures in order to get accurate and relevant analytical results. HP,OS

  5. Educational Requirements • Requirements for a general careers in this field: • formal education equivalent of a bachelor's degree in chemistry or closely related field • bachelor's degree in biology • two years experience in a forensic laboratory • approval of the S.O.M. • School of Medicine HP,OS

  6. Analytical Procedures • Collection from Clothing or Other Items • Visual examine item • Take care to preserve evidence and other sections such as blood, stains, and latent prints • At this point, you may use tape to remove stray hairs and dust off the fiber • Label tape lifts • Identify fiber type and color • Place in envelope to store HP,OS

  7. Presumptive Tests • They are preliminary tests/field tests • Establishes possibility of a specific bodily fluid’s presence • Do not conclusively prove the presence • Pros: • Narrows possibilities • Can be used on larger areas • Can locate possible evidence not visible to naked eye • Cons: • Risk of false positives and may be overly sensitive HP,OS

  8. Presumptive Tests • Phenolphthalein Test • Aka: Kastle Meyer Test • A Phenolphthalein solution is used to show the possible presence of blood based upon a reaction of hemoglobin which produces a pink color. • Precautions: This test is presumptive because it has produced false positives HP,OS

  9. Presumptive Tests • Luminol Test • Luminol is used in solution or sprayed onto suspected surfaces. This compound gives a strong blue fluorescence (glows)when viewed with a UV light. It is used o find blood reminants • Precautions: False positives have been observed with the presence of copper salts HP,OS

  10. Blood Typing KE

  11. Universal Types • People with type AB blood are called universal recipients • No antibodies present • Can receive blood from anybody • People with type O blood are called universal donors • No antigens present • Can donate blood to anybody KE

  12. Interpreting Blood Stain Patterns • Satellite Spatter: Small droplets of blood that are distributed around the perimeter of a drop/drops of blood and were produced as a result of the blood impacting the target surface • Skeletonization: The outside of a blood droplet will harden before the center • Drip Trail Pattern: A pattern of bloodstains formed by the dripping of blood of a moving surface or person in a recognizable pathway separate from other patterns AM,AC

  13. Interpreting Blood Stain Patterns • Arterial Spatter: A characteristic blood stain pattern containing spurts that result from blood exiting under pressure from an arterial injury • Expirated Blood Pattern: A pattern created by blood that expelled out of the nose, mouth, or respiratory system as a result of air pressure and/or air flow • Void: Something that takes the place of the blood at a crime scene AM,AC

  14. Interpreting Blood Stain Patterns • Transfer: A bloodstain pattern created when a wet, bloody surface comes in contact with a second surface. • Low Velocity Spatter: Blood that falls at a normal gravity speed, typically from an open wound • High Velocity Spatter: Blood that is flown at a speed greater than that of gravity that is associated with high-speed collisions, such as gunshots or explosions AM,AC

  15. Interpreting Blood Stain Patterns • Impact Spatter: a random pattern of spatter of varying sizes • Forward Spatter: Blood that travels away from the source in the same direction as the force that caused the spatter • Back Spatter: Blood directed back toward the source of the force that caused the spatter AM,AC

  16. What is Crime Scene Reconstruction? • The use of scientific methods, physical evidence, deductive reasoning and their interrelationships to gain explicit knowledge of the series of events that surround the commission of a crime. JH

  17. Who Participates In Crime Scene Reconstruction? • Reconstructing consists of the following: • Medical Examiner • Experienced Law Enforcement Personnel • Criminalists JH

  18. Steps of Crime Scene Reconstruction • Recognition of evidence • Documentation of evidence • Collection of evidence • Evaluation of evidence • Hypothesis • Testing • Reconstruction JH

  19. Crime Scene Reconstruction • The criminalist must be prepared to answer the following questions when examining dried blood • Is it blood? • From what species did the blood originate? • If the blood is of human origin, how closely can it be associated to a particular individual • Detection of blood is best made by means of a preliminary color test KE

  20. Things To Consider At The Crime Scene • Origin(s) of bloodstain • Distance of bloodstain from target • Direction from which blood impacted • Speed with which blood left source • Position of victim and assailant • Movement of victim and assailant • Number of blows/shots KE

  21. Which type of blood? • Once the stain has been characterized as blood, the precipitin test will determine whether the stain is of human or animal origin • Once the bloodstain has been determined to be of human origin, the blood is typed Test For Human Blood KE

  22. Blood Group Characteristics • Based on 2 glycolipid antigens (A & B) found on the surfaces of RBC • Antigen A only= type A blood • Antigen B only= type B blood • Both antigens= type AB blood • No antigens= type O blood KE

  23. Glossary • Agglutination: the clumping together of red blood cells by the action of an antibody • Angle of Impact: acute or internal angle formed by the direction of a blood drop and the plane of the surface it strikes • Antibody: a protein in the blood serum that destroys or inactivates a specific antigen • Antigen: a substance, usually a protein, which stimulates the body to produce antibodies against it • Anti-Serum: blood serum that contains specific antibodies • Area of Convergence: The area containing the intersections generated by lines drawn through the long axes of individual stains that indicates in two dimensions the location of the blood source. • Area of Origin: the location of the blood source in 3-D perspective • Arterial Spray: Bloodstain pattern(s) resulting from blood exiting the body under pressure from a breached artery • Back Spatter: A bloodstain pattern resulting from blood drops that traveled in the opposite direction of the external force applied; associated with an entrance wound created by a projectile. • Blood Drops: gravity acts on the blood until it impacts a horizontal surface • Blood Smears :these happen when a bleeding person is moved • Blood Splashes: blood that has been thrown through the air until it struck a surface at angle AW

  24. Glossary Cont. • Blood Spurts: this is result of arterial bleeding • Blood Trails: blood that is deposited when a wounded person walks or runs while dripping blood. It can also happen from carrying or dragging a body • Drip Trail: A bloodstain pattern resulting from the movement of a source of drip stains between two points. • Forward Splatter: A bloodstain pattern resulting from blood drops that traveled in the same direction as the impact force. • High-Velocity Impact Spatter: bloodstains resulting from blood with a velocity in excess of 100 ft per sec • Impact Spatter: A bloodstain pattern resulting from an object striking liquid blood. • Low-Velocity Impact Spatter: bloodstains resulting from blood with a velocity of 5 ft per sec or less • Luminal: a liquid that reacts to UV lighting and reveals that traces of blood • Medium Velocity Impact Spatter: bloodstains resulting from blood with a velocity of 5 ft to 25 ft per sec • Plasma: the liquid part of the blood • Pools of Blood: these pools are next to the body and may indicate if the body has been moved AW

  25. Glossary Cont. • Satellite Spatter: A smaller bloodstain that originated during the formation of the parent stain as a result of blood impacting a surface • Serology: the scientific study of blood • Skeletonization: A bloodstain consisting of a darkened peripheral rim where the center of the stain is no longer intact. • Spattered Blood: a random distribution of bloodstains that vary in size that may be produced by a variety of mechanisms • Transfer Patterns: A bloodstain resulting from contact between a blood-bearing surface and another surface • Void: An absence of blood in an otherwise continuous bloodstain or bloodstain pattern. AW

  26. Works Cited • http://hemospat.com/terminology/index.php?cat=misc&sub=skeletonized • http://www.crimeandclues.com/index.php/forensic-science-a-csi/crime-scene-investigation/crime-scene-reconstruction/4-introduction-to-crime-scene-reconstruction • http://www.wisegeek.com/what-are-the-different-crime-scene-investigator-jobs.htm • http://www.cienciaforense.com/Pages/CrimeScene/CSReconstruction.htm

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