A panel drug test is a standardized screen designed to detect a specific grouping of substances, and the number in the name refers to the classes of drugs being analyzed. The 8-panel drug test is a common, non-federally mandated standard often used by private employers for pre-employment, post-accident, or random drug screening. This format offers a broader scope than the more basic 5-panel test by including several prescription drug classes that have a high potential for misuse. The test determines the presence of drug metabolites, which are the byproducts created as the body breaks down a substance.
The Eight Classes of Substances Screened
The 8-panel drug test identifies eight distinct classes of commonly misused substances. Amphetamines, including prescription stimulants like Adderall and illicit substances like methamphetamine, are screened for their powerful stimulant effects. Cocaine is detected through its primary metabolite, benzoylecgonine, which can remain detectable for a short period after use.
Marijuana (Cannabinoids) is identified by tracing the presence of Delta-9-tetrahydrocannabinol (THC) and its metabolites. Because THC metabolites are fat-soluble, they can be detected for a significantly longer time than many other drugs. Opiates are a broad class that includes natural compounds like codeine and morphine, as well as their semi-synthetic derivative, heroin. Phencyclidine (PCP) is a dissociative anesthetic that produces hallucinogenic effects, and testing for it is standard in this panel.
Two classes of prescription sedatives are included to detect potential misuse. Barbiturates, such as phenobarbital, are central nervous system depressants historically used for anxiety and seizure control. Benzodiazepines, which include medications like Xanax and Valium, are tranquilizers often prescribed for anxiety or sleep disorders. The final class is Methadone, a synthetic opioid used in medication-assisted treatment for opioid use disorder, which is also subject to diversion and misuse.
Collection Procedures and Sample Types
The integrity of the drug test relies on strict adherence to the Chain of Custody procedure, which documents every sample transfer. Although an 8-panel test can use oral fluid or hair, urine is the most common sample type due to its cost-effectiveness and longer detection window. The collection process begins with verifying the donor’s identity using photo identification and completing a Custody and Control Form (CCF).
The collector ensures the collection area is secure and free from potential adulterants, often by adding blue dye to the toilet water and restricting access to water sources. Immediately after the donor provides the specimen, the collector checks the temperature of the sample within four minutes. The temperature must fall within 90°F to 100°F to confirm it is a freshly voided sample.
The collected sample is then split into two containers: the primary specimen for initial analysis and a split specimen held in reserve for potential retesting. Both containers are sealed with tamper-evident tape, and the seals are initialed by the donor to confirm the sample’s integrity.
Understanding Test Results and Confirmation
Upon arrival at the laboratory, the sample first undergoes an initial immunoassay screening test. This rapid, cost-effective method uses antibodies to detect drug metabolites above a predefined cutoff level. If the initial screen is non-negative, the primary sample proceeds to the second, more definitive phase of testing, and the split specimen is not immediately opened.
The confirmatory test employs advanced analytical techniques, such as Gas Chromatography/Mass Spectrometry (GC/MS) or Liquid Chromatography/Mass Spectrometry (LC/MS). These methods precisely separate and identify the chemical structure of the drug metabolites, confirming both their presence and concentration. This process minimizes the possibility of a false positive result from the initial screening.
The final result is sent to a Medical Review Officer (MRO), a licensed physician specializing in substance abuse testing, rather than directly to the employer. If the lab confirms a positive test, the MRO contacts the donor to determine if there is a legitimate medical explanation, such as a valid prescription. Only after the MRO completes this review and finds no valid medical reason is the result reported as confirmed positive to the ordering entity.