Keberhasilan Identifikasi Sampel Darah Kering yang Dipaparkan pada Beragam Jenis Substrat Kayu dengan Kondisi Lingkungan Berbeda Selama Kurun Waktu Tertentu

Abstract

Most of the criminal cases leave traces at the TKP (Tempat Kejadian Perkara) which can be used as evidence to reveal the culprit and the chronology of events that have occurred. Blood is the most important biological evidence in TKP. Through experimental research with a completely randomized design (CRD), this study aims to determine the success rate of blood groups identification in different types of Sengon (Paraserianthes falcataria L. Nielsen) as wood substrate in open and closed environmental conditions up to a certain time period. The four variations of Sengon wood substrate used were natural wood, processed wood, painted wood, and varnished wood. After 336 hours exposure on wood substrate, blood sample on the substrate was confirmed to identify the ABO system blood group using the absorption-elusion method. The results showed that the success rate identification the blood groups in ABO system on all types of Sengon wood substrate in closed environmental conditions reached a 100% for observation periods until 336 hours. Despite, the success rate of blood identification from all types wood substrate in open environmental condition were 0% for observation periods until 336 hours. Those data was then tested for normality with SPSS. The results showed that the data are not normally distributed (sig >0,00) for all type of treatmment. So that non-parametric statistical tests were carried out. The results of the Kruskall Wallis test showed that there was no significant difference between the treatment of Sengon wood substrate types and also in the length of time of observation (sig value 1,000). While the significance value on the environmental condition variable is 0.000, so it was concluded that there was a significant success rate's differences of blood group identification in samples that exposed to an open environment compared to a closed environment. This is reinforced by the results of the Kendall's correlation test and Spearman's test which show a strong correlation between the percentage of successful identification of blood groups and environmental conditions (correlation of 1,000). While the correlation value between the percentage of successful identification of blood group with the type of substrate and the length of time of exposure are 0.000 and 0.000, which is indicates a very weak correlation between the percentage of success of blood group with the type of substrate and the length of time of exposure. It can be concluded that the four types of wood substrates in closed environmental conditions had the same good ability to preserve blood within an exposure time of up to 336 hours. But, sample exposure in a closed environment provides the best percentage of success rate identification the blood groups in ABO system rather than the open environment was.