What is the primary purpose of a presumptive test in forensic analysis?

• A. To indicate possible presence of a substance
• B. To confirm the exact identity
• C. To quantify the amount present
• D. To determine the source of a substance

Answer: (A)

Presumptive tests are screening tools in forensic analysis. They’re designed to quickly indicate whether a substance might be present in a sample by producing simple, rapid reactions (often color changes) that suggest a broad class of compounds. Because these tests are not highly specific, a positive result doesn’t confirm exact identity—it only signals that there could be something of interest, prompting further, confirmatory testing with more precise methods like GC-MS or FTIR. They’re used to triage evidence, not to quantify how much is present or to determine where the material came from.