The age estimation of blood stains up to 30 days old using visible wavelength hyperspectral image analysis and linear discriminant analysis

A novel application of visible wavelength hyperspectral image analysis has been applied to determine the age of blood stains up to 30 days old. Reflectance spectra from selected locations within the hyperspectral image, obtained from a portable instrument, were subjected to spectral pre-processing. This was followed by the application of a linear discriminant classification model, making estimations possible with an average error of ± 0.27 days for the first 7 days and an overall average error of ± 1.17 days up to 30 days. This is also the first reported study of the determination of the age of fresh blood stains (less than one day old) with an error of ± 0.09 h. The studies have been made under controlled conditions and represent, at this stage, proof of concept results but also are the most accurate age estimation results for measurements between 0 and 30 days reported to date. The results are consistent with well-established kinetic processes suggesting that the pre-processing stages described are revealing spectroscopic changes which are reliably following the time dependent oxidation of HbO₂. The potential for parameterisation of environmental factors to make the method generally applicable at crime scenes is discussed, along with the developments required to further improve classification and to make the instrument genuinely portable.     

The detection of HIV antibodies in blood stains

Blood samples were collected on cotton wool and stored at +20 degrees C. These samples were tested in an enzyme linked immunosorbent assay and the immunoblotting test. HIV-antibodies could be detected in samples stored up to four month.     

Micromethod for the detection of erythrocyte antigens in blood stains

A micromethod was developed to allow the analysis of blood stains of minor size by the absorption elution technique. The individual absorption, washing, and elution steps were carried out in Beckman tubes containing 5 microliter antiserum. The final agglutination reaction was read through the inverted microscope in microtest plates regularly used for HLA typing. For this final reaction, 2-4 microliter eluate was incubated with 2,000 red blood cells suspended in 1 microliter saline and supplement. For the purpose of standardization, the intensity of agglutination in the microtest plate had to be defined. In comparison to the standard method (tube test and centrifugation), the proposed method proved to be slightly more sensitive with regard to the Rhesus and slightly less sensitive with regard to the AB0 system. With the proposed method very small traces could be successfully analyzed. Thus, two cotton threads 1 mm in length were sufficient for testing antigens A and B, and two cotton threads 2.5 mm in length were enough to detect an Rh antigen.     

Blood typing of blood stains on sweat stains by the iso-agglutinins detection method

When a blood typing is made for mixed stains of sweat and blood, erroneous results may be obtained. The reason is that the blood group substance in the sweat is detected at the same time as that in the blood. In this paper the typing of the blood stain on the sweat stain is carried out by the detection of isoagglutinins which may give additional information to the forensic serologist.     

The effect of temperature on Y-chromosome detection in blood stains

The present investigation is an extension of an earlier work on the effect of various temperatures on Y-chromosome detection. The deteriorating effect of storage at 53 °C was again demonstrated. Liquid blood samples stored at 5 °C were better preserved with regard to Y-chromosomes than those stored at room temperature. This was in conflict with the earlier results on blood stains. New experiments were therefore performed. The results varied. It is suggested that this variation was due to low temperatures having two contrary effects on the results: the well-known preserving effect on biological material and a previously described constricting effect on the heterochromatic areas of the chromosomes making Y-body detection more difficult.     

The use of hybrid isoelectric focusing for the detection of polymorphic proteins in blood stains

alpha1-Antitrypsin (Pi), transferrin (Tf) and orosomucoid (ORM) were determined in bloodstain extracts by isoelectric focusing (IEF) with carrier ampholytes (CA) and also with a mixture of immobilines (HIEF). HIEF yields superior results from proteins typing in bloodstain extracts, since phenotypes are better distinguished and the bands are straighter and sharper. Also the sensitivity of HIEF is similar to IEF with CA.     

On the detection of minor Rhesus antigens in blood stains

A new method for the detection of minor C, Cw, c, E, e-antigens of the Rhesus system in blood stains has been developed based on the absorption-elution technique with the use of anti-C, anti-Cw, anti-c, anti-E, and anti-e sera and standard erythrocyte preparations preliminarily treated with highly active proteases (protease C or papain). This method makes it possible to determine complete Rhesus phenotype in blood stains and substantially extend the possibilities of their differentiation on material objects (evidence) for the purpose of forensic-biological examination.     

A sequence of tests of minute human blood stains for human origin identification and ABO blood grouping

A series of examinations is presented for human origin identification and ABO blood grouping of doubtful minute human blood stains. A blood-stained thread (0.5 cm in length) was first tested to identify human origin by microprecipitation method and then the ABO blood type was determined by both a modified absorption-elution test and a modified mixed agglutination. In the continuous tests, the maximum limits of positive reactions of the microprecipitation method, the modified absorption-elution test, and the modified mixed agglutination were 1:640, 1:160, and 1:2,560 diluted blood, respectively. A and B agglutinogens were more sensitively determined than H agglutinogen. Hemagglutinogens of blood stains on cotton threads were more easily detected than those of polyester ones.     

Human blood stain identification and sex determination in dried blood stains using recombinant DNA techniques

DNA was extracted from human and non-primate dried blood stains. Human male and female specimens were readily distinguished by analysis with a Y-chromosome specific DNA probe. Human and non-primate blood stains were also readily differentiated using a repeat sequence (Alu) DNA probe. The potential power of recombinant DNA analysis in forensic science is discussed.     

The use of the obti test for determining the presence and type of blood in stains

A method for simultaneous detection and identification of the blood in stains on material evidence has been tried. Previously these two procedures were carried out in succession and took 2 days, while the new method takes 2-10 min. The method is highly sensitive and specific. Positive results were obtained only with human blood. The method is recommended for practice, specifically, for investigation of complex blood traces (washed and old) on material evidence.     

Electronic data processing latex immunoassay for the identification of human seminal stains

Electronic data processing (EDP) latex immunoassay using anti-human seminal acid phosphatase (anti-HSAP) immune serum was applied for the species and organ identification of human seminal stains. This test proved to be highly sensitive and specific.