Effects of different environmental factors on the identification of fetal and adult hemoglobin in bloodstains

ABSTRACT

The forensic scientist is confronted with many problems in the identification of bloodstains. These problems may be due to the aging of the stain or some environmental factors to which the stain was exposed. The aim of this work is to determine the effects of different environmental factors [age, temperature, pH, light, dark, humidity, open air and burn] on fetal hemoglobin [HbF] and adult hemoglobin [HbA] identification. The study aims also to determine the recommended conditions for collection and preservation of bloodstains. The research was carried out on 20 blood samples of healthy adult volunteers and 20 fetal human blood samples. Fetal hemoglobin [HbF] was measured in fetal blood samples and total adult hemoglobin [HbA] was measured in adult blood samples by cyanomethemoglobin method and their patterns were detected by cellulose acetate electrophoresis method. The results demonstrated that fetal and adult hemoglobin concentration decreased with the advance of the age of the stain. The percent of decrease due to aging was more in fetal hemoglobin. The minimal effect of temperature was after exposure to -4°C [the percent of decrease was 29.49% for fetal and 21.99% for adult]. Fetal hemoglobin appeared to be more resistant to alkalis and acids; more affected by both light and dark than adult hemoglobin. The study of the pattern of cellulose acetate electrophoresis revealed that the studied environmental factors had great destructive effects on blood stains but fetal hemoglobin [HbF] was more affected than adult hemoglobin [HbA]. The study recommended that bloodstains must be preserved in a dry condition at -4°C without addition of any chemicals or just in open air where analysis must be done as early as possible