Analisis Perbedaan Variasi Derajat Keasaman terhadap Tingkat Spesifisitas Metode Kastle-Meyer dalam Pendeteksian Darah

Blood is evidence of a crime that can be damaged by humans and environmental factors. One of the contaminants that have the potential to affect the specificity of the Kastle-Meyer method in detecting blood is the variation in the degree of acidity (pH). Specificity analysis of the Kastle-Meyer method is needed to determine the ability of the Kastle-Meyer method to detect blood in the presence of other components/contaminants that may be present in a sample. The purpose of this study was to analyze the difference in the addition of an acidic solution with a pH of 1.2-8.4 on the specificity of blood detection using the Kastle-Meyer method. The research was conducted in the form of pre-experimental research with a static-group comparison design. The sampling technique used was purposive sampling. Blood samples that have been added to an acid solution with a certain pH (pH 1,2; 2.4; 3.6; 4.8; 6; and 7.2) were then tested using the Kastle-Meyer method. The principle of the Kastle-Meyer method is based on the activity of the peroxidase enzyme present in hemoglobin in the blood. The results showed the specificity of the Kastle-Meyer method on blood samples with acid solution contaminants with a pH of 1.2; 2,4; 3,6; 4.8; 6.0; 7.2; and 8.4 respectively at 70%, 70%, 90%, 60%, 60%, 90%, 80%. The results of data analysis from the Kruskal-Wallis test showed a significance p-value 0.269 > 0.05, so it can be concluded that there is no difference in the specificity of the Kastle-Meyer method in detecting blood in the addition of acid solutions with different acidity degrees.