Opinion ID: 1285369
Heading Depth: 1
Heading Rank: 3

Heading: Areas of Concern

Text: Three major areas of concern exist when dealing with electrophoresis of forensic blood stains. One is the problem of contamination. Contamination of the blood sample may occur from substances such as dirt, gasoline, sweat and the like. For protein/enzyme typing, the problem of contamination is dealt with by the experience of the analyst in recognizing banding patterns. Internal variations in the banding pattern of a particular protein indicate to the analyst whether the pattern is being altered by contamination. When contamination is noted, a typing determination is not made and the result is classified as indeterminate. A second area of concern is deterioration of the proteins as a blood sample ages. The proteins and enzymes lose their activity with age, but there is no conversion in form from one protein/enzyme to another. Therefore, there is no problem that a protein will be mistyped. Rather the banding pattern becomes so faint as to be unreadable. When the pattern becomes too faint, the result is classified as indeterminate. The final area of concern is the fact that the sample is dried blood rather than liquid blood. Dried blood samples, however, have been determined to be more reliable than liquid samples, because they remain stable over longer periods of time.