Bodily fluids

What are bodily fluids

Liquids produced by human body. Contain biological information that can link individuals to a crime/provide valuable evidence.

Blood

Fresh/Dried bloodstains

Blood splatter patterns - provide insight into dynamics of a crime scene

Plasma can be tested for drugs and toxins

White blood cells contain DNA

Platelet activity can help determine timing of injuries, severity of trauma

Blood tests

Presumptive:

• Chemiluminescence - luminol - reaction causes blood to fluoresce

• Catalytic tests: Kastle meyer - pink is positive reaction, Leuchomalachite green: green is positive reaction

Confirmatory test:

• Microscope assessment

• Crystal tests

• Spectroscopy

Saliva Tests

Tests for amylase

Saliva added to soluble starch solution with iodine

Phadebes test

Semen

Contains sperm cells - DNA

Seminal fluid

Semen tests

Presumptive:

• ALS

• Acid phosphatase - detects enzyme in semen

Confirmatory:

• Microscope analysis: christmas tree stain

• RSID Semen strip test

Vaginal Fluid

Not as commonly found

Variations due to hormonal changes - menstrual cycle

Vaginal Fluid tests

None routinely used

Periodic Acid Schiff reagent detects glycogenated epithelial cells

Menstural fluid

Has to be distinguished from normal blood - is it natural bleeding or trauma

Menstrual fluid test

SERATEC PMB detects haemoglobin and d-dimer

Urine

Difficult to detect due to low sensitivity of tests, its diluted and dispersed, odour not localised.

Urine tests

Urease breaks down urea producing ammonia - detected using Nesslers/DMAC reagent

Creatinine detected using Jaffe test

THP protein detected using RSID urine test

Sweat

least common bodily fluid found at crime scenes

Contains water and mineral traces

Sweat tests

SEMEDX

G81

Metabolite biometrics