Identifying Biological Evidence in Forensics

Biological Evidence

Samples collected for forensic analysis.

Serology

Analysis of blood and bodily fluids.

Presumptive Testing

Initial test indicating potential substance presence.

Hemoglobin

Protein in red blood cells carrying oxygen.

Plasma

Liquid component of blood containing serum and fibrinogen.

Catalytic Color Tests

Tests using oxidation to detect blood.

False Positives

Incorrect positive results from non-blood substances.

False Negatives

Negative results despite blood presence.

Kastle-Meyer Test

Common presumptive blood test using phenolphthalein.

Chemiluminescence

Light emitted from a chemical reaction.

Fluorescence

Light emitted when exposed to specific wavelengths.

Semen

Fluid containing sperm cells ejaculated by males.

Spermatozoa

Mature male reproductive cells.

Azoospermia

Absence of sperm cells in semen.

Acid Phosphatase

Enzymes indicating presence of semen.

Christmas Tree Stain

Staining method for sperm cell visualization.

Saliva

Alkaline secretion aiding in digestion.

Amylase

Enzymes breaking down starches and sugars.

Starch Iodine Test

Test indicating starch presence by color change.

Alternate Light Sources

Tools for detecting biological fluid stains.

Electrolytes

Minerals in blood aiding various bodily functions.

Confirmatory Tests

Tests providing definitive identification of substances.

Visual Examination

Initial step to locate blood evidence.

Chemical Oxidation

Reaction involving loss of electrons.