TEICHMANN confirmative test for blood identification in stains

Abstract

The analysis of blood identification in dry spots is carried out using the Teichmann crystallographic method as a basis to the colorimetric orientation tests in the expert work of the Forensic Biology laboratories of the National Institute of Legal Medicine and Forensic Sciences To determine by Teichmann's crystallographic method its sensitivity, specificity, positive predictive value, negative predictive value, limit of detection, concordance index and Kappa index according to the different conditions of temperature, support and medium in which they are located. 100 samples of dry spots are taken to be analyzed double-blind, in different substrates using the Teichmann confirmatory method for blood identification, following the adequate biosecurity measures by the Forensic Biology Laboratory. The statistical quality values obtained in sensitivity were 96,22%, 100% Specificity, 100% Positive Predictive Value, 96,87% Predictive Negative Value, 1/100 Detection Limit, 100% Concordance Index and a Kappa Index. of 1. Through the data obtained, the effectiveness of Teichmann's crystallographic method as a confirmatory test in support of presumptive methods of orientation in the identification of blood in spots is made manifest.