Validation Studies of an Immunochromatographic 1-Step Test for the Forensic Identification of Human Blood

Abstract

An immunochromatographic 1-step test for the detection of fecal occult blood was evaluated for applicability for the forensic identification of human blood in stained material. The following experiments were conducted: 1) determination of the sensitivity and specificity of the assay; 2) evaluation of different extraction media for bloodstains (sterile water, Tris buffer pH 7.5 provided in the test kit, 5% ammonia); 3) analysis of biological samples subjected to a variety of environmental insults; and 4) evaluation of casework samples. This immunochromatographic 1-step occult blood test is specific for human (primate) hemoglobin and is at least an order of magnitude more sensitive than previous methods for detecting human hemoglobin in bloodstains. The antigen is insensitive to a variety of environmental insults, except for exposure to certain detergents and household bleaches and prolonged exposure to certain preparations of luminol. The entire assay can be conducted in field testing conditions within minutes. When in the laboratory the supernatant from a DNA extraction is used for the assay, there is essentially no consumption of DNA for determining the presence of human hemoglobin in a forensic sample. The data demonstrate that this test is robust and suitable for forensic analyses.

Multiplex mRNA profiling for the identification of body fluids

“…For example, blood identification is carried out by crystal tests such as the Takayama test or by immunochemical or immunochromatographic means in which a human-specific antiserum to serum proteins or hemoglobin produces a precipitated or captured antigenantibody lattice upon diffusion or electrophoresis [1,2]. Similarly, semen is identified by the microscopical confirmation of spermatozoa or the immunochemical or immunochromatographic identification of prostate-specific antigen (PSA or p30) [3,4].…”

“…parallel) analysis procedures for body fluid identification that are compatible with current DNA analysis procedures, we initially considered assays based upon proteins and messenger RNA (mRNA) since both are expressed in a tissue-specific manner. However, multiplex analysis of complex, partially www.elsevier.com/locate/forsciint Forensic Science International 152 (2005) [1][2][3][4][5][6][7][8][9][10][11][12] degraded protein mixtures, such as those present in body fluid stains, awaits further developments in proteomics. Messenger RNA is considered a better option at present because the technologies for massively parallel analysis continue to be developed due to rapid advances in the field of functional genomics.…”

Los enterramientos neolíticos de Ca l’Arnella (Terrassa, Barcelona)

“…Empleamos un kit Hexagon OBTI, que permite reconocer mediante la reacción de determinadas proteínas la existencia de restos de hemoglobina de primates (Hochmeister et al 1999) . Desconocemos por qué los resultados fueron negativos .…”

A interferência da solução de luminol em teste imunocromatográfico para pesquisa de sangue humano

“…Para tal, são realizados testes de maior especificidade, como a imunocromatografia, método esse realizado em uma membrana cromatográfica que contém anticorpos imobilizados e móveis dotados de capacidade de identificação da hemoglobina humana [16,17].…”

“…Refêrencia [18] mostra que os testes de certeza podem ter a intensidade de seus resultados diminuída pelo luminol. Um estudo também demonstrou que uma das preparações de luminol prejudicou o teste imunocromatográfico Hexagon OBTI® [16]. Já outro experimento comprovou que o pH da amostra alterado pelo uso do luminol interfere no teste imunocromatográfico OC-Hemocard (Alfa Wassermann) [13].…”