Concentra Explained – Services, Testing, and Drug Screening Explained

Concentra is the largest provider of occupational health services in the United States by number of locations—a distinction that reflects not just scale, but a focused specialization that sets it apart from general clinical laboratory networks. Where most large labs serve the full breadth of medical diagnostics, Concentra’s core business is built around the health and safety of the working population: treating workplace injuries, conducting employment-related physical exams, managing workers’ compensation cases, and administering drug and alcohol screening programs for employers across the country.

Understanding what Concentra does, and how its drug testing services work in particular, is useful for employers building compliance programs, employees navigating a screening requirement, and anyone seeking to understand how occupational health fits into the broader U.S. healthcare system.

Company Background

Concentra was founded in 1979 in Amarillo, Texas, originally under the name OccuSystems Inc., by Dr. Richard Rhem. Over the following decades, the company grew through a combination of organic expansion and acquisitions, passing through periods of ownership under Humana and later Select Medical before becoming a fully independent, publicly traded company.

In July 2024, Concentra Group Holdings Parent, Inc. completed its initial public offering on the New York Stock Exchange under the ticker symbol CON, pricing shares at $23.50. Select Medical completed a full distribution of its remaining Concentra equity to its own stockholders in November 2024, making Concentra a fully standalone public company. The company is headquartered in Addison, Texas.

As of early 2025, Concentra operates more than 552 occupational health centers across 41 states and 157 onsite health clinics at employer worksites across 36 states, plus its telemedicine platform, Concentra Telemed. The company employs approximately 11,000 colleagues and affiliated physicians and clinicians, serves more than 50,000 patients per day on average, and maintains relationships with more than 200,000 employer partners nationwide. Revenue for the 12 months ended March 31, 2024 was approximately $1.8 billion.

Concentra’s stated mission is “improving the health of America’s workforce, one patient at a time.”

What Concentra Does: Core Services

Concentra is not a general clinical laboratory. It does not process routine blood panels for general health monitoring or run diagnostic testing for chronic disease management the way a reference lab does. Its services are organized around one central question: what does an employer need to maintain a safe, healthy, and legally compliant workforce?

The company’s core service areas include:

Drug Testing at Concentra: An Overview

Drug testing is one of Concentra’s most widely used employer services. The company administers both regulated testing—programs governed by federal law, primarily through the Department of Transportation—and non-regulated testing for private employers designing their own drug-free workplace policies.

Concentra uses FDA-approved automated and instrumented technology for its screening processes. Non-negative results and all regulated drug tests are forwarded to a federally certified, SAMHSA-approved laboratory for confirmation analysis.

The four specimen types Concentra uses for drug testing are: urine, oral fluid (saliva), hair, and blood. Not all specimen types are available for all testing purposes or in all states.

Types of Drug Tests

Urine Drug Testing

Urine testing is the most widely used method and is the only specimen type accepted for federally mandated DOT drug testing programs. It is cost-effective, well-established, and capable of detecting a broad range of substances. Concentra offers both rapid (point-of-collection) urine testing and laboratory-based urine testing.

With rapid urine testing, a negative result is identified on-site within minutes. Any non-negative result is sealed and sent to a SAMHSA-certified laboratory for confirmation, which typically takes three to five business days. Laboratory-based urine testing bypasses the on-site screen and goes directly to the lab, where an initial immunoassay screen is run followed by confirmation testing if needed.

Oral Fluid (Saliva) Drug Testing

Oral fluid testing involves a swab of the mouth to collect a saliva sample. It is less invasive than urine testing, and collection is directly observed, reducing the risk of specimen tampering. Oral fluid testing has a shorter detection window than urine—typically one to two days—making it particularly effective for detecting recent or on-the-job drug use rather than historical patterns.

Concentra notes that oral fluid testing is useful in situations where an employer wants to distinguish between recent substance use and use that occurred days or weeks prior—a distinction that has become particularly relevant in states where cannabis has been legalized. Oral fluid testing is available for non-regulated employment screening in certain states. In May 2023, several DOT agencies amended their regulations to permit oral fluid as an alternative to urine for regulated programs, subject to laboratory certification requirements.

Hair Drug Testing

Hair testing analyzes a small sample of head hair—typically 1.5 inches, representing approximately 90 days of growth—to detect the presence of drugs embedded in the hair shaft from the bloodstream. This gives hair testing the longest detection window of any specimen type Concentra offers.

Hair testing is not permitted under DOT drug testing regulations, but it is widely used by non-DOT employers who want visibility into historical drug use patterns. Per applicable state law, hair and blood testing are not available in Hawaii, Maine, or Vermont. A standard hair drug test with initial screen and confirmation requires approximately 100 milligrams of hair.

Blood Drug Testing

Blood testing detects substances in the bloodstream directly, making it the most accurate method for establishing current impairment. However, drugs are metabolized and cleared from the blood relatively quickly, giving blood testing the shortest detection window of any specimen type—roughly 10 to 48 hours depending on the substance. It is also the most invasive and expensive option. Blood testing at Concentra is a non-DOT, lab-based screen, typically reserved for specialized circumstances such as immediate post-accident situations where active impairment is suspected.

Drug Panels: What Substances Are Tested

Rather than detecting drugs directly, most drug tests identify metabolites—chemical byproducts the body produces as it processes a substance. The specific substances included in a screen depend on which panel the employer selects.

The Standard 5-Panel (DOT and Non-DOT)

The federally mandated DOT 5-panel covers five drug classes required for safety-sensitive transportation employees. The same panel is also the standard baseline for many non-DOT programs.

Drug Class Primary Metabolite(s) Detected
Marijuana (cannabis) THC-COOH (tetrahydrocannabinol carboxylic acid)
Cocaine Benzoylecgonine
Opiates Morphine, codeine, 6-acetylmorphine (heroin marker)
Amphetamines Amphetamine, methamphetamine, MDMA, MDA
Phencyclidine (PCP) PCP

The 10-Panel and Intermediate Options

Non-DOT employers seeking broader screening can choose from expanded panels. Concentra offers non-regulated panels in 5- and 10-panel configurations, as well as intermediate 6-, 7-, 8-, and 9-panel options. A 10-panel test typically adds the following to the standard five:

Additional Drug Class Examples
Benzodiazepines Diazepam (Valium), alprazolam (Xanax), chlordiazepoxide (Librium)
Barbiturates Phenobarbital, butalbital, secobarbital
Methadone Synthetic opioid used medically and illicitly
Propoxyphene A prescription pain reliever class
Oxycodone Oxycodone and related metabolites

Oral fluid screens can additionally detect alcohol alongside the standard panel substances.

“No-THC” Panel Options

Concentra offers “no-THC” panel configurations for non-regulated drug screens in most states. This allows employers operating in states where cannabis is legal to screen for other controlled substances without testing for marijuana, which some employers now choose to exclude from their programs given shifting legal and policy landscapes.

Detection Windows by Specimen Type

Detection times are not fixed values. They are influenced by dose and frequency of use, the substance’s half-life, individual metabolism, hydration levels, and the specific cutoff thresholds applied by the testing program. The ranges below reflect Concentra’s published guidance and are approximate.

Specimen Type Approximate Detection Window Best Use Case
Blood 10–48 hours Suspected current impairment
Oral fluid 1–2 days Recent or on-the-job use
Urine 2–4 days typical; longer for chronic users General pre-employment and random screening
Hair Up to approximately 90 days Historical drug use patterns

How the Drug Testing Process Works

Concentra’s testing process follows a standardized chain-of-custody workflow designed to ensure results are accurate, legally defensible, and compliant with applicable regulations.

  1. Employer Registration and Donor Authorization: The employer creates a test order through Concentra’s online system. This generates secure documentation the employee brings to a nearby Concentra medical center. The employer receives notifications at key stages: when the test is complete, if additional lab analysis is required, and when final results are ready.
  2. Arrival and Identification: At the center, the donor presents a valid, government-issued photo ID. Personal belongings are set aside during specimen collection.
  3. Specimen Collection: A trained collector explains the process and collects the specimen per required protocol. For urine, the donor provides a sample in a private restroom. The collector reads the specimen temperature within four minutes of collection—urine must fall between 90°F and 100°F to be accepted. A reading outside this range is documented on the Custody and Control Form (CCF) and may trigger an observed recollection. For oral fluid and hair, collection is directly observed.
  4. Chain-of-Custody Documentation: The specimen is sealed with tamper-evident labels in the donor’s presence, and both the donor and the collector sign the CCF. This form tracks the specimen from collection through final reporting, providing a documented record of every hand-off.
  5. Screening: For rapid tests, an initial immunoassay screen is performed on-site and a negative result is available within minutes. For lab-based tests, the sealed specimen is shipped to a SAMHSA-certified laboratory where an immunoassay screen is run.
  6. Confirmation Testing (If Needed): Any specimen that screens non-negative proceeds to confirmatory analysis using gas chromatography/mass spectrometry (GC/MS) or liquid chromatography with tandem mass spectrometry (LC/MS/MS). These techniques precisely identify and quantify specific molecules at the molecular level. A result is reportable as a confirmed positive only if the detected metabolite meets or exceeds the applicable cutoff concentration.
  7. Medical Review Officer (MRO) Review: Non-negative results are reviewed by a Medical Review Officer—a licensed physician (MD or DO) with specialized training in substance abuse disorders, toxicology, and drug testing regulations. The MRO contacts the donor directly to determine whether a legitimate medical explanation, such as a valid prescription, accounts for the result. If a satisfactory explanation is verified, the MRO may report the result to the employer as negative. If no valid explanation exists, the result is verified as positive.
  8. Results Reporting: Final verified results are securely transmitted to the employer. Concentra provides 24/7 online access to results through its employer portal. For routine tests, results are typically available within 24 to 48 hours. Non-negatives requiring lab confirmation and MRO review generally take three to five business days.

DOT Drug Testing

Employers in DOT-regulated industries—commercial trucking, aviation, rail, mass transit, and pipeline operations, among others—are required by federal law to conduct drug testing under the procedures defined in 49 CFR Part 40. Concentra is an established provider of DOT-compliant drug testing, covering all six mandated testing scenarios: pre-employment, random, post-accident, reasonable suspicion, return-to-duty, and follow-up testing.

DOT testing uses only urine as the specimen type and covers only the federal 5-panel. Employers regulated by the DOT cannot modify the panel by adding or removing substances. Concentra also provides DOT physical examinations performed by certified Medical Examiners and manages drug consortium memberships for smaller employers required to maintain random testing pools under DOT regulations.

Breath alcohol testing (BAT)—both DOT-regulated and non-regulated—is also available through Concentra’s network, performed by trained Breath Alcohol Technicians using federally approved evidential breath testing devices.

Summary

Concentra is a specialized occupational health provider, not a general diagnostic laboratory. Its services are purpose-built around the needs of employers and the working population: treating injuries, conducting compliance-related screenings, and administering drug and alcohol testing programs. With more than 625 medical centers nationwide, over 400 onsite employer clinics, and partnerships with more than 200,000 employers, it is the most extensive occupational health network in the country by location count.

Its drug testing services cover four specimen types—urine, oral fluid, hair, and blood—with configurable panels ranging from the federally mandated 5-panel to expanded 10-panel configurations and intermediate options in between. The process is governed at every step by chain-of-custody documentation, SAMHSA-certified laboratory analysis, and Medical Review Officer oversight, producing results that satisfy the legal and regulatory requirements of both DOT and non-DOT programs.

Employers designing a testing program and individuals preparing for a screening should consult Concentra’s employer services team or their own legal and HR advisors, as applicable panel options, state-specific restrictions, and compliance requirements vary by jurisdiction and industry.