False Positives in Luminal Testing

Abstract

The blood sample is one of the most essential pieces of evidence that helps criminal experts in the elucidation of the crime. However, cleaning the blood found at the crime scene after the crime is committed makes it difficult to detect the crime. Therefore, experts have attached great importance to research on blood samples left at the crime scene. Although many test kits are used, especially in detecting erased blood, the luminol kit is widely used at crime scenes. In the luminol kit, the reaction takes place with the addition of hydrogen peroxide (H2O2). Since it is known that hydrogen peroxide can react with other substances containing Fe (II) ions that may be present in the environment during the reaction, it was aimed to carry out research to determine which substances luminol interferes with, especially those that may be found in a domestic crime scene in this study. In domestic crime scenes, there are limited substances that can replicate the distinct, enduring luminescence characteristic of a reaction between luminol and genuine bloodstains, while the uncharacteristic glow produced from many other surfaces is likely to be recognised with the naked eye by a good expert, experienced and knowledgeable in the field. In this regard, the prepared samples were treated with luminol in a dark environment, and the reactions occurring in the first seconds were recorded. The results obtained with this reagent are recommended to be supported by other blood test reagents or confirmatory tests, as there are substances that give false positive results with luminol reagents in the present study.