Bloodstain dried

It has been determined that although human blood is one of the most common clue materials found at crime scenes, laboratory analysis procedures are comparatively undeveloped in the United States. The major limitations appear to be the unavailability of simple and rapid methods of analysis, the lack of high quality antisera prepared specifically for dried bloodstain analysis, and the absence of blood frequency distribution data for the population of the United States. The LEAA-sponsored program at Aerospace, therefore, is intended to improve the methods for the detection of genetic variants in dried blood, to expand the data base concerning frequency of distribution of these variants, and to design a structure for the future collection and dissemination of such data. 

The final objective will be directed toward the determination of the sexual origin of bloodstains by measuring the levels of testosterone and estradiol in dried blood. 

Current research involves the use of radioimmunoassay to quantitate testosterone and estrogen in dried blood samples (22, 24). The ultimate goal of this research will be to determine the sexual origin of the stains. In the past, researchers have attempted this by identifying Barr bodies and Y chromosomes using differential fluorescence staining with quinacine however, these tests required a substantial amount of blood deposited as a thin film on a non-porous surface and are therefore limited in their application (19, 20, 21). The sensitivity and basic technique of radioimmunoassay will permit the analysis of bloodstains on virtually any surface and should also be applicable to very small ones. 

A, AB, B, CB, AC and C. From numerous distribution and family studies it has been determined that the six phenotypes are directed by three common alleles pa, p, and pc (2,3, ). Using crude hemolysates ( 5) and 1,000 fold pure homogeneous type AA and BB enzymes (6) some properties of EAP, such as thermostability, pH and substrate specificity and molecular size, have been examined. From the time EAP polymorphism was first described, the use of the enzyme as a means of typing human blood has been of interest to the forensic scientist. Investigators have described successes in typing dried bloodstains stored at 20 - 25 C for 5-8 weeks and stored whole blood kept at 5 C was typed for as long as 15 months ( 7). Difficulties in typing EAP types AB (1,3), B and C (J3 ) have also been described. 

The purpose of this study was to compare two electrophoretic methods used to type EAP and to examine the stability of EAP phenotypes in red cell hemolysates, clotted blood and dried bloodstains stored at room temperature (25°C). A distribution study of the frequency of five EAP phenotypes among ABO, MN, Rh blood groups and among 137 metropolitan Washington D. C. area residents was made. The effect of neuraminidase on EAP was also studied. 

Dried bloodstains were prepared by pipetting a mixed suspension of red cells onto a clean piece of white cotton sheeting which was then completely air dried. Accurately cut 10mm x 2mm cuttings were used for electrophoresis. 

Stability of EAP during storage at 25°C. The loss of EAP activity in dried bloodstains, fresh cell hemolysates, and clotted blood during storage at 2S°C is shewn in figure 4. Hemolysates and clotted blood lost nearly all EAP activity after storage for 5 days at 25°C while EAP activity in dried stains persisted for much longer periods of time. The loss of activity of all five different EAP phenotypes was the same in hemolysates and clotted blood stored at 25°C. In dried bloodstains, however, EAP phenotypes CB and AC lose activity at a slower rate than do types AB, A and B. Type A is the least stable of the phenotypes. Type AE was intermediate between types B and A. 

Figure 4. Comparison of the loss of EAP activity present in red cell hemoly-sates, clotted blood, and dried bloodstains stored at 25°C. EAP phenotypes shown are types A, AB, B, CB, and AC.

As shown in table 1, dried bloodstains retain EAP activity for periods as long as 15 months. Dried bloodstains were typed blind up to 4 months without difficulty but beyond that period typing became very difficult. Dried bloodstains that could be typed after 4 months were saturated and required long incubation periods in the presence of freshly prepared thiol reagents. 

TABLE 1. EAP TYPING OF AGED-DRIED BLOODSTAINS STORED AT 25 C... 

Figure 5. Densitometer tracings illustrating the loss in activity of the b isozyme of EAP phenotype CB in a dried bloodstain stored at 25°C...

All five types lost essentially all typeable activity in 5-6 days under these conditions. In dried bloodstains, differences in the rates of loss in activity of the five EAP types was observed. Types CB, AC and B were observed to be the most stable,while type A was the least stable. Type AB is intermediate between types A and B. Dried bloodstains were typed blind up to 20 weeks but beyond that point caution should be exercised. 

Occasional changes in activity of the b isozyme of types B and CB during storage at 25 C in clotted and dried bloodstains were observed. This phenomerm is consistent with observations made by Luffman and Harris ( 5). During thenrostability studies with five EAP phenotypes they found that the activity of the faster moving component (b isozyme) of type B became weaker as it was heated for 5 minutes at 52 C while the activity of the slower component (c isozyme) became stronger. Both isozymes lost essentially all activity after 10 minutes. 

When it is a question of bloodstains, the sampling technique will be as important as the storage conditions as far as later examination is concerned. Contamination and high humidity conditions that promote maceration must be absolutely avoided (transport in plastic containers is excluded). A dried bloodstain must be stored frozen for blood group typing. Certain blood characteristics will be preserved if kept cold, even over many years (ABO, Gm), while others will disappear after a much shorter delay. 

Many clinical chemistry assays are based on UVAfIS spectrophotometry, often by reaction of the chemical of interest, snch as glucose, with an enzyme and dye to create a colored complex. A novel method for determining the age of dried bloodstains at a crime scene has been developed by researchers at the National Center for Forensic Science at the University of Central Horida using the Implen NanoPhotometer Pearl (Hanson and Ballantyne). The researchers discovered a previously unidentified hypsochromic shift (a blue shift to shorter wavelengths) in the Soret band of hemoglobin =412... 

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