What Quest Diagnostics does and who uses it

Quest Diagnostics is a private laboratory company that performs drug tests for employers, courts, probation departments, and individuals. It operates more than 2,000 patient service centers across the United States, making it one of the largest drug-testing providers in the country. When an employer, court, or other organization orders a drug test, they often contract with Quest to collect the sample and run the analysis.

Quest does not decide whether you take a test — your employer, a court order, a probation condition, or another entity makes that decision. Quest's role is to collect your sample, send it to their laboratory, and report the results to whoever ordered the test. Understanding how Quest operates helps you know what to expect when you arrive for testing and what happens to your sample afterward.

Key Takeaways

  • Quest Diagnostics operates thousands of testing centers where you provide a urine, hair, saliva, or blood sample depending on what was ordered.
  • The person collecting your sample will watch the collection process for urine tests to prevent tampering, and you may be asked to remove outer clothing or empty your pockets.
  • Quest sends your sample to a laboratory for analysis, and results typically come back within 24 to 48 hours, though some employers receive them faster.
  • If your test shows a positive result, Quest may perform a confirmation test called a GC-MS before reporting it to the ordering party.
  • You can request a copy of your test results, and you have the right to request that your sample be sent to a different laboratory for independent testing if you dispute the result.

Finding a Quest Diagnostics location and scheduling

Quest Diagnostics locations are listed on their website, where you can search by zip code or city. Many employers and courts provide you with a specific location and instructions, but if you need to find one on your own, the search tool shows hours, address, and phone number for each center. Some locations accept walk-ins, while others require an appointment — calling ahead prevents a wasted trip.

If your employer or court ordered the test, they typically give you a requisition form or a reference number. Bring this document with you, along with a government-issued photo ID. Without the requisition, the testing center may not know what type of test to perform or who to report results to.

What happens during sample collection

The collection process depends on the type of test ordered. For a urine test, you will be taken to a private bathroom where a Quest employee observes the collection to prevent sample tampering. You may be asked to remove outer layers of clothing, empty your pockets, and wash your hands before and after providing the sample. The collector seals the sample container with your information and a unique identifier.

Hair tests involve cutting a small sample of hair from the back of your head — typically about 100 strands — and take only a few minutes. Saliva tests require you to spit into a collection tube. Blood tests are drawn by a phlebotomist using a needle. The entire process, regardless of type, usually takes 10 to 15 minutes from check-in to completion.

After collection, Quest labels your sample with a barcode and your identifying information. The sample is then sent to a Quest laboratory for analysis. You do not receive results at the testing center — Quest reports them to whoever ordered the test, and that party may or may not share the results with you depending on your situation.

How Quest analyzes samples and reports results

Quest uses immunoassay screening as the first step, which detects the presence of drug metabolites in your sample. If the screening is negative, that result is reported. If the screening is positive, Quest typically performs a second test called gas chromatography-mass spectrometry (GC-MS) to confirm the result before reporting it. This confirmation step reduces false positives.

Results are usually reported within 24 to 48 hours, though some employers receive expedited results within a few hours. The ordering party — your employer, court, or probation officer — receives the report first. They then decide whether and how to share the results with you. In employment situations, your employer typically notifies you of the outcome. In legal situations, the court or probation department informs you.

Quest reports results as negative, positive, or inconclusive. A positive result means the test detected a substance above the threshold level set by the ordering party. An inconclusive result means the test could not determine a clear outcome and may require retesting.

What drugs Quest tests for and detection windows

The substances tested depend on what the ordering party requested. A standard five-panel test screens for marijuana, cocaine, amphetamines, opioids, and phencyclidine (PCP). Extended panels may include benzodiazepines, barbiturates, methadone, or other drugs. Some employers or courts order tests for alcohol as well, which requires a different sample type.

Detection windows vary by substance and sample type. Urine tests typically detect drug use within the past 2 to 4 days for most substances, though marijuana can be detected longer in regular users. Hair tests can detect drug use over the past 90 days. Saliva tests detect recent use, usually within the past 24 hours. Blood tests show the most recent use, typically within hours to a few days.

Your rights if you dispute a result

If you believe your test result is wrong, you have the right to request that your sample be retested at a different laboratory at your own expense. This is called a split sample test or independent confirmation. You must request this within a specific timeframe — usually within 72 hours of receiving your result — so act quickly if you plan to pursue this option.

You also have the right to request a copy of your test results from Quest. Contact the testing center where you provided your sample or call Quest's customer service line. Some results are released directly to you, while others are released only to the ordering party depending on who paid for the test and local regulations.

If you believe the collection process was improper — for example, if you were not observed correctly or if the sample was mislabeled — document what happened and report it to the ordering party. They may decide to order a new test or investigate the concern.

Frequently Asked Questions

Can I refuse to take a drug test at Quest Diagnostics?

You can refuse, but the consequences depend on who ordered the test. If your employer ordered it as a condition of employment, refusing may result in termination. If a court or probation department ordered it, refusing may be considered a violation of your probation or court order. The ordering party, not Quest, decides what happens if you refuse.

How long does it take to get results back?

Most results are reported within 24 to 48 hours. Some employers receive expedited results within a few hours. The ordering party receives results first and then shares them with you according to their own timeline and policies. Inconclusive results may take longer because they require retesting.

What if I take prescription medications that might show up on the test?

Tell the collector about any prescription medications you are taking before the test begins. Quest's laboratory technicians know which medications can produce positive results and may note this in the report. The ordering party then decides whether to investigate further or accept the result based on your disclosure.

Can I see the actual lab report or just the pass/fail result?

You can request a copy of your full lab report from Quest, though some results are released only to the ordering party. Call the testing center or Quest's customer service to request your results. The report will show what substances were tested for, the screening result, and any confirmation test results.

What happens if my sample is lost or damaged?

If your sample cannot be tested, Quest will contact the ordering party to request a new sample. You may be asked to return to the testing center for recollection. Document the date and time you provided your original sample in case there are questions about the timeline.