The main goal of the Serology Unit is to identify areas on submitted items that may contain bodily fluids. These pertinent stains are then documented, collected, and preserved for possible DNA testing at a later date. The body fluids typically searched for are blood and seminal fluid. Serologists use physical, chemical, and biological tools to examine evidence for these stains.
The Serology Section relies mainly on the skills and knowledge of the individual examiners as well as on basic equipment, chemical and biological exams. In many cases, this unit is the first stop for evidence. The powerful tool of DNA analysis is contingent in many situations on locating and identifying body fluid stains on the evidence--and finding these useful biological stains is the main focus of the Serology Unit.
Although evidence may come in many shapes and sizes, there are guidelines that allow for examinations to proceed in a sensible order, and throughout all of the examinations and testing of evidence, detailed notes are kept. This may include diagrams and photographs.
First, items are examined for their physical characteristics and at this point trace materials may also be collected. Although some stains may not be visible to the human eye, many are and the trained examiner looks thoroughly at each item to determine what stains merit additional testing. The next step may be to enhance the visual examination by using an alternate light source. In this way, stains may be located and then tested using chemical and biological means.
When pertinent body fluid stains are located then either the entire item, a collection from the item, or a portion of the item is preserved in a freezer. The low temperatures may help to maintain the stability of the collected materials.
The situation of the particular case is always important to consider. Sometimes the relevant information sought may be from whom the body fluid came, and other times it may be that determining the nature of the stain is the piece of information needed. The location of staining on an item may also be very significant in determining certain aspects of what may have happened. The results of these examinations relative to the case details may allow investigators to focus on suspects and to exclude, or exonerate, other individuals.