What type of test is commonly used to verify the presence of drugs in a substance?

Qualitative analysis is commonly used to determine the presence or absence of a specific substance, such as drugs, within a sample. This type of testing focuses on identifying the components of the substance rather than measuring the amount present. In the context of drug testing, qualitative analysis provides a straightforward method to confirm whether a particular drug is present, often using techniques like color tests, immunoassays, or chromatography.

Quantitative analysis, on the other hand, is used to determine the specific concentration or amount of a substance in a sample. While this information can be crucial in understanding the extent of drug use or exposure, it does not directly address the presence of the drug itself—only how much is there. Confirmatory testing is typically a follow-up procedure employed after qualitative analysis to definitively identify the substance, often involving more sophisticated methods to corroborate initial findings. Therefore, the core function of qualitative analysis aligns with the need to verify whether a drug is present in the substance tested.