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Laboratory Orientation and Testing of Body Fluids and Tissues for Forensic Analysts


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Image of urine sample
National Institute of Justice (NIJ) (see reuse policy).

Urine contains a large amount of urea, a chemical byproduct of normal metabolic processes in the body.  Identification of high levels of urea can therefore serve as a screening test for urine in fluids or stains.  The presence of creatinine is also used for screening purposes. Creatinine forms a red compound with picric acid (known as the Jaffe Test).  Urine also has a characteristic odor, which can help in locating its presence. Gentle heating of urine-stained materials gives rise to a distinctive odor.

Urine from secretors will contain ABH substances.  This is a source of contamination in testing underclothing.

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