In bloodstain analysis, what does a screening test do?

In bloodstain analysis, a screening test is primarily designed to check if the material in question could be blood. This initial assessment is crucial for forensic investigations, as it helps to narrow down the evidence that may need further analysis. Screening tests can involve various methods, such as colorimetric tests or enzyme-based assays, which react specifically with components in blood, indicating its presence. The goal of these tests is not to provide detailed information about the blood, such as its type or source, but to confirm that the sample is indeed blood, thus allowing investigators to focus on more specific analyses afterward.

While identifying the blood type, analyzing for drugs, and determining the source are all vital aspects of forensic science, they require more advanced tests and are not the primary function of a screening test. The screening step serves as a foundational filter, ensuring that a forensic analyst is working with relevant biological material.