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Diagnostics and Forensic Science. Diagnostics Services Diagnosis – determining the cause of an illness or condition Clinical Laboratory Scientists or.

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Presentation on theme: "Diagnostics and Forensic Science. Diagnostics Services Diagnosis – determining the cause of an illness or condition Clinical Laboratory Scientists or."— Presentation transcript:

1 Diagnostics and Forensic Science

2 Diagnostics Services Diagnosis – determining the cause of an illness or condition Clinical Laboratory Scientists or Medical Technologists often do the tests Done in hospitals and independent labs; often requires specific machines Reference Range – averaging the test results for large population + 2 S.D; helps define what is in “normal” ranges

3 Diagnostic ServicesCareers Blood Urinalysis Culturing Biopsy Rapid Diagnostic Tests Home Medical Test kits Imaging Genetic Tests Pathologists Medical Lab Technologist/Technicians Nuclear Lab Technologists Phlebotomists Radiologists Radiology Technologists

4 Uncertainty of Testing Sensitivity – measures how often someone who has the condition tests positive Specificity – measures how often someone who does not have the condition test negative

5 Forensics What is forensic medicine? Latin word - forensics Means public discussion or debate Science used in justice system for legal purposes Facts based on scientific investigation Goal is to determine facts and truth Uses multiple science specialties

6 Autopsies Definition and Purpose To see for oneself Surgical operation done on a dead body To learn about person’s health and cause of death Legal Requirements Coroner Medical examiner Pathologist

7 Autopsies Reasons for autopsy Determine which disease or injury caused death Diagnosis - confirmation and understanding Evaluate possible public health issue Preparation If not required by law, permission needed from next of kin Legal consent form

8 Autopsies Procedure Complete medical history and review of records External physical exam Body tag Weight and height Clothing and valuables identified Scars, tattoos, injuries, wounds, bruises recorded Foreign objects noted Photos and x-rays taken, if needed

9 Autopsies Complete internal exam Dissection of head and abdomen Organs removed, weighed, measured, and examined Tissue samples examined under microscope Fluid samples tested for drugs, infection After autopsy complete, legal death certificate Results Natural death – disease or old age Unnatural death – unnatural, unexpected, or unusual cases

10 Autopsies Methods to determine time of death Traditional indicators Rigor mortis Begins three hours after death in face and eyelid muscles Takes twelve hours to affect entire body Process reverses after 36 hours Lividity (hypostasis) Visible minutes after death Red cells settle and skin below turns red In 6-10 hours, color becomes permanent

11 Autopsies Body temperature Falls at rate of one degree per hour Obesity and warm environment slows cooling Forensic Entomology Involves the life cycle of insects which is predictable None of the above are totally reliable and can be manipulated

12 DNA Analysis Deoxyribonucleic Acid make of a chain of nucleotides consisting of a deoxyribose sugar, a phosphate (PO 4 ), and a nitrogenous base (A,T,C,or G) Double stranded and helical (twisted) with A’s of one strand pairing with T’s of the other strand; G and C also pair up complementary. 3 billion base pairs in human genome and 21,000 genes DNA 95% similar to chimpanzee DNA sequence highly conserved among different species

13 DNA Analysis Used to identify people; uses 13 Short Tandem Repeats (STR) sequences found throughout genome Used to identify ancestory and relatedness Also used to diagnose probability of having a genetic disease Can be used to access treatment options Can be used for newborn screening

14 DNA Techniques Karyotyping – technique to look at an organisms chromosomes; allows us to determine chromosomal mutations Polymerase Chain Reaction – copies DNA molecules in vitro Gel Electrophoresis – allows us to cut and and visualize DNA fragments while studying them. Microarrays – allow scientists to study gene expression of 1000s of genes to determine if they are turned on or off at a particular time; good for studying cancer.

15 Forensic Anthropology Skeletal anatomy 206 bones Man = 12 pounds Woman = 10 pounds What bones show How person lived Debilitation illnesses (rickets, polio, healed fractures) Right handed or left handed Clues to occupation

16 Forensic Anthropology Questions about skeletal remains Age of person at time of death Sex of person (skull and pelvis) Race Height

17 Forensic Odontology 1.Characteristics of teeth after death a.No other part lasts longer b.In fires, teeth usually only means to ID remains c.No two people have identical teeth 2.Requirements for identification a.Need dental records b.Dentists chart five surfaces of each tooth in a grid (odontogram) c.Can also provide “bite mark” evidence 3.Teeth useful in determining subject’s age

18 Forensic Toxicology Investigate drugs and poisons in the body (hair, blood, urine, etc) Use Gas Chromatograph/Mass Spectrometer (GC/MS) to analyze the components of samples to identify the drug/poison or its metabolites in the sample Can determine amount of substance and whether it could have had negative impact on victim resulting in death. Analytical chemist


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