Detection of Biological Traces

Detection of biological material and determination of its nature

is the first step in handling evidence that arrives at the lab for analysis; this aims at then choosing the most appropriate method of sampling, isolating and analysis genetic material.

Technology

A. Detection of biological material

The detection of biological material on evidence is carried out using a UV lamp. This device emits ultraviolet light, which causes the sites where the material is deposited to fluoresce. In this way, we can check whether visible stains contain biological material or if there are other deposits that are not visible to the naked eye.

Β. Determination of the nature of biological material

After detecting the biological material, guiding tests then are applied which will point to its nature, i.e. if it is blood, saliva, semen or other biological material.

1. Detection of blood

To detect blood, 3 different tests are applied depending on the needs of each case.

General blood detection by observing the catalytic action of the haemoglobin molecule when oxidising phenolphthalein and the substrate changes colour (Kastle-Meyer Test)
Detection of human blood by immunodetection of the human haemoglobin molecule (HemDirect Test)
Detection of very low quantities of blood of any origin, which are not visible to the naked eye or that are found on dark surfaces, by chemiluminescence, even after thorough cleaning (BlueStar Test).

2. Detection of semen

General detection of sperm by observing the catalytic action of the acid phosphatase molecule which changes the colour of the substrate (Acid Phosphatase Test)
Detection of human sperm by immunodetection of the human prostate-specific antigen molecule (PSA Test).