DNA extraction from blood determination membrane card test.

ABSTRACT

Among the several techniques applied in our laboratory, in order to establish human nature of blood specimens we perform an immunodiagnostic analysis through a specific membrane test card, which is usually utilized as a fast screening test for human haemoglobin in diagnostic checks. This test works with a double-step method based upon solubilization of the sample in a proper buffer and its migration on a membrane monoclonal and polyclonal antibodies specific against haemoglobin are linked to. The complexes haemoglobin-antibodies migrate through the membrane and are revealed by an immunoreactive line turning reddish-coloured to show that the reaction took place and the system works. As this test can recognize both the whole haemoglobin molecule and the degraded one, it is usually exploited in forensic sciences to detect kind and species of blood specimens related to forensic case works. However, as a consequence of the small amounts of blood in the samples collected from the crime scene we often cannot perform this kind of analysis in order to save the sample and be able to genotype it. Then, we investigated the possibility to purify DNA from the blood specimens already dissolved in the extraction buffer and perform STR typing on it with several methods and after different storage conditions and time.