Identification of Urine
- urine is waste product of mammalian physiology
- urine can vary from one mammal to another and also within the same species
- some factors that affect urine analysis
- diet (meats)
- time of day sample is collected
- medication
- health
Importance of Urine as Evidence
*Urine-drug tests
~ identity of the donor DNA
~ more cellular material found in female urine samples than in males
* relaxation of sphincter muscles of bladder upon death can lead to release of urine
*if body is moved from crime scene original location of urine can be of importance
Identification of Urine: Methods
Detects Urea and Creatinine
Tests to detect Urea and Creatinine
Litmus Paper Test (urease)
DMAC
Creatinine Picrate
NONE OF THESE METHODS ARE CONFIRMATORY TESTS*
Creatinine is a product of ____
Creatin
Locating Urine Stains
Flourescence
- UV light (color varies)
- ALS (flourescesses weakly under different wavelengths)
- Odor (gentle heating)
Urea -Enzymatic Tests: Urease
Urease catalyze a decomposition of Urea
Urea + water –> CO2 + 2NH3
Handling Evidence containing urine
- items of evidence suspected of containing urine should be air dried, and kept refrigerated or frozen if possible
- DO NOT USE PLASTIC to store any stains -use paper bags or paper envelopes
- liquid urine should be refrigerated
- exposure to environmental insult should be kept to a minimum (i.e. Rain, heat, soil)
Physiology of Urine
- urine is formed in kidneys by filtering out waste products from the blood
- urine is then transferred from the kidneys to the bladder by the Ureter
- the urine is then removed from the body through the urethra
- amount of urine produced per day varies
Physiology of Urine
- amount is directly influenced by liquid intake,heat, and physical activity of individual
- urea is the principal breakdown product of proteins and the amount found in urine is directly related to diet
- urea is an end product of metabolism
Urea
the principal breakdown product of proteins and the amount found in urine is directly related to diet
A,B,O
AB
Karl Landsteiner (1901) AB = 1902
A,B,H(O)
Antigenic activities often referred to as ABH activity are found in sugar linkages of ikigosaccharides present on two types of molecules
- glycosphingolipids
- glycoproteins
History of Urine Analysis
- soluble glycosphingolipids are present in plasma but not secreted in other bodily fluids
- soluble glycoproteins with ABH activities are present in serous and mucous secretions (BGS Gets involved)
- approx 80% of population who carry Se gene are secretors
- presence of this gene is necessary for expression of the ABH activity in various body fluid secretions
History of Urine Analysis 2
- non secretors (sese) are individuals who secrete small amounts of glycoproteins but have little or undetectable levels of ABH activity
- approx 20% of population are non secretors
Examination of Urine Evidence-Odor
- smell of urine is due partly to the presence of ammonia formed from the bacterial breakdown of urea *Gentle heating can help detect this odor
- if stain is dilute it may not give off the unique odor
In addition to BGS humans can also be differentiated based on the presence of____
Polymorphic enzymes Plasma Proteins (polymorphic proteins)
Polymorphic Enzymes
Proteins inside the RBC that mainly serve as catalysts for converting one substance to the other
Plasma Proteins (polymorphic proteins)
Proteins mainly used for transport
Urine contains a large amount of ___
Urea
Urea
Chemical byproduct of normal metabolic process of the body
Urine also contains ______
Creatinine
Breakdown product of of Creatine
Creatinine
Creatinine
Waste product that is excreted from the body entirely by the kidneys
