Identification of Saliva and Other Body Fluids

Saliva Production

1 - 1.5 L produced daily.

Composition of Saliva

Largely water with electrolytes, proteins, enzymes, antibodies, and epithelial cells

Sublingual Glands

Contribute ~5% to saliva production.

Submandibular salivary Glands

Account for ~70% of saliva production.

Parotid salivary Glands

Contribute ~25% to saliva production.

There are currently no confirmatory methods in use for saliva

true

Saliva Presumptive Tests

Identify saliva using inorganic anions (thiocyanate and nitrate) and enzymes. (alkaline phosphatase or a-amylase)

Alkaline Phosphatase

Enzyme used in saliva identification tests.

Alpha-Amylase

Breaks down starch by hydrolyzing a 1-4 bonds. (works only on straight chains)

AMY 1

Salivary locus of alpha-amylase.
- expressed in saliva, perspiration, and breast milk

AMY 2

Pancreatic locus of alpha-amylase.
- found in semen, urine, fecal material, vaginal secretions

Amy 1 & 2 are highly homologous and antibodies will recognize both

true

Amylose

Linear glucose polymer with a 1-4 linkages.

Amylopectin

Branched glucose polymer with a 1-6 linkages.

Debranching Enzyme

Hydrolyzes 1-6 linkages at branch points.

Amylose chain

forms helixes with 6 glucose residues per turn

Iodine reaction color from shortest to longest chain

< 12 glucose residues/2 helical turns= no color --> brown-->red-->purple--> blue (> 9 helical turns)

Starch Iodine Radial Diffusion Test

Starch with Iodine creates a blue color
• If saliva is present, amylase will break down the starch creating a clear ring in the blue that is measured

Starch Iodine Radial Diffusion Positive Test Results

the ring size is equal or greater in size than the positive control

inconclusive Starch Iodine Radial Diffusion result

the ring size is less than the positive control but greater than the negative control

negative Starch Iodine Radial Diffusion result

absence of any clear ring

Phadebas Test

Blue dye covalently attached to the starch if amylase present, it will release a blue dye into the solution

SALIgAE Kit

Commercial test for saliva presence.
Simple, sensitive (~1:1000)
• Reported to be more accurate than other tests
• Changes color with addition of an extract containing saliva
• Exact mechanism - proprietary

SALIgAE® positive Test results

A yellow color change indicates a positive result

SALIgAE® negative test result

No color change, indicating no saliva present or is below the limit of detection of the test

RSID Saliva

Immunochromatographic test for salivary amylase.

RSID saliva sample well

If target amy-1 antigens are present, they bind to mobile monoclonal anti-human salivary a-amylase antibodies that are conjugated to colloidal gold.

Test zone

The antibody-antigen complexes bind to immobilized monoclonal antibodies, leading to a visible color change if the target is present.

Control zone

Confirms the test's functionality by capturing some colloidal gold-labeled antibodies, showing a second line.

Is RSID saliva test confirmatory or presumptive?

presumptive because it cross reacts with perspiration and breast milk

what is the sensitivity of RSID saliva test?

1 microliter

Urine tests are useful in sexual assaults involving

urination; In Homicides involving ligature or manual strangulation, victims often involuntarily excrete urine prior to death

Urine Formation

Occurs in kidneys; eliminates metabolic wastes.

Urinary System

Eliminates soluble toxic wastes that are cellular metabolic by-products and consists of kidneys, ureter, bladder, and urethra

Waste (ions, ammonia, urea, etc) are secreted through the _________ to the ___________ before its excreted through the ___________

ureter, bladder, urethra

which organ is filtered to reabsorb water, glucose, nutrients

kidneys

What is urea?

Most abundant waste product in urine.

Where does urea come from?

Elimination of ammonia produced from metabolic process of amino acids.

Inorganic Ions in Urine

Includes Cl-, PO4^3-, SO4^2-.

Urine Identification

Odor and inorganic ion tests used.

DMAC presumptive test

detects amines (particularly urea) when reacted with Acetone/HCl, it will turn dark pink/red indicating
possible presence of urine

Creatinine

creatinine picric acid w/base turns bright red

Tamm-Horsfall Protein

Most abundant protein in urine.
-synthesized in epithelial cells of kidney
- Biological function not fully understood

Immunochromatographic Test

Used for confirming presence of body fluids.

Vaginal Secretions

No current tests available in US labs.

Menstrual Blood Testing

New methods under development for identification.

Fecal Material Testing

Involves macroscopic (color, odor) and microscopic (undigested foodstuff) examination, testing detects urobilinoids

Immunochromatographic Menstrual blood test

presumptive bc it identifies peripheral blood and menstrual blood