Note: Definitions are expressed in terms applicable to the subjects of drug testing and pharmacology. Some terms may possess inherently different meanings when applied to other fields of study.

•  Accuracy: The ability of a test device to produce a reading that matches the known value for the sample.
•  Amnestic: An agent used for the treatment of impaired memory function.
•  Analgesic: An agent that relieves pain selectively without affecting consciousness or sensory perception.
•  Anesthetic (General): An agent that produces unconsciousness as well as diminishing or eliminating the sensation of pain.
•  Anesthetic (Local): An agent that diminishes or eliminates the sensation of pain on or in the specific region of the body where it is applied.
•  Antihyperbilirubinemic: An agent used for the treatment of antihyperbilirubinemia (jaundice) - a common disorder in newborns wherein the chemical "bilirubin" accumulates in the infant's blood and causes a yellow hue.
•  Antitussive: An agent that suppresses coughing.
•  Anxiolytic: A mild sedative used for relief of anxiety.
•  Cannabinoid: Any of the active principles of Cannabis Sativa (marijuana), including, but not limited to, THC.
•  Central Nervous System (CNS): Body system comprised of the brain and spinal cord.
•  Central Nervous System (CNS) Depressant: An agent that diminishes brain and/or spinal cord function or activity.
•  Central Nervous System (CNS) Stimulant: An agent that amplifies brain and/or spinal cord function or activity.
•  Cross-reactivity: The degree in which substances other than the target compound are shown to generate positive test results.
•  Cutoff Concentration: The specific concentration of drug or drug metabolite in the sample that is chosen as a limit to distinguish a positive from a negative test result. Samples with concentrations above the cutoff level are considered positive and results below are considered negative.
•  Depressant: An agent that diminishes a body function or activity.
•  False Negative Test Result: A test result which states that no drug is present when, in fact, a tested drug or metabolite is present in an amount greater the cutoff concentration.
•  False Positive Test Result: A test result which states that a drug or metabolite is present when, in fact, the drug or metabolite is not present or is present in an amount less than the cutoff concentration.
•  Hallucinogen: An agent that distorts sensory perceptions, sometimes resulting in sensory illusions which may be mild or extreme.
•  Hypnotic: An agent that induces sleep.
•  Interference: The effect that a compound (or group of compounds) has on the accuracy of test measurement.
•  Metabolite: A modified form or byproduct of a drug produced by the body's metabolic process.
•  Narcotic (Narcotic-Analgesic): An agent that relieves pain through depression of the central nervous system.
•  Negative Test Result: A test result which states that no drug or metabolite is present or no drug or metabolite is present in an amount greater the cutoff concentration.
•  Positive Test Result: A test result which states that a drug or metabolite is present.
•  Precision: The ability of a test device to produce the same value during repeated measurements.
•  Quantitative Test Result: A test result expressed in numerical terms in order to determine the specific quantity of drug or drug metabolite present in the sample.
•  Qualitative Test Result: A test result expressed in non-numerical terms in order to determine the presence or absence of drug or drug metabolite in the sample.
•  Reproducibility: The ability of a test device to produce the same value during repeated measurements in various laboratories which are participating in a collaborative study.
•  Sedative: An agent that calms nervousness, irritability, and excitement. In general, sedatives depress the central nervous system and tend to cause sluggishness and reduced mental activity.
•  Sedative-Hypnotic: An agent that calms nervousness, irritability, and excitement and/or induces sleep. In general, sedative-hypnotics depress the central nervous system and tend to cause sluggishness and reduced mental activity.
•  Sensitivity: For quantitative test devices: The smallest concentration of a drug or drug metabolite that produces a response distinguishable from the background or blank value. For qualitative test devices: The minimum concentration of a drug or drug metabolite that is capable of generating a positive test result. In qualitative test devices, this amount is generally the same as the cutoff concentration.
•  Specificity: The ability of a test device to determine exclusively the drug and/or drug metabolites that are claimed to be detected without cross-reacting with other related substances that are not intended to be detected.
•  Stimulant: An agent that amplifies a body function or activity.
•  Target Drug/Metabolite: The drug or metabolite that the test device is designed to detect.
•  Tranquilizer: An agent used for relief of anxiety.