Oral fluid, commonly called a mouth swab or saliva test, works on a different scale than urine testing. The federal government sets specific cutoff concentrations for oral fluid because saliva carries drugs at much lower levels than urine, and it captures the parent drug rather than the metabolites urine testing typically targets. This guide walks through the cutoff levels the Department of Health and Human Services has authorized, where the Department of Transportation stands on allowing oral fluid for safety sensitive employees, how the cutoffs built into rapid point of care devices can differ from the federal table, and what an employer should confirm before adding oral fluid to a testing program.
What a cutoff level actually means
A cutoff is the concentration of a drug or its marker, measured in nanograms per milliliter, that a specimen must meet or exceed to be reported as presumptively positive on the screening test, and again on a separate confirmatory test. Two cutoffs matter for every analyte. The initial, or screening, cutoff is used on the immunoassay device or instrument that flags a specimen as nonnegative. The confirmatory cutoff, which is almost always lower, is the threshold a laboratory uses on a mass spectrometry method to verify that specific drug is present at a quantifiable level. A specimen has to clear both thresholds before a laboratory reports it as positive, and a Medical Review Officer still reviews any nonnegative result before it becomes a reportable positive.
Oral fluid cutoffs generally run lower than urine cutoffs for the same drug class, and the guidelines specify that the levels apply to undiluted, or neat, oral fluid, not a diluted extract. That matters because the collection devices used for oral fluid mix a swab with a buffer solution, and the cutoff math has to account for that dilution factor to arrive at the reported result.
HHS oral fluid cutoffs, the authorized panel
The Department of Health and Human Services first published Mandatory Guidelines for oral fluid testing in the Federal Register, and those guidelines became effective for federal workplace testing programs in October 2023, alongside a companion rule that gave HHS authority to update the authorized panel, its analytes, and its cutoffs annually through a separate Federal Register notice, without needing full notice and comment rulemaking each time. The table below reflects the authorized oral fluid panel and cutoffs HHS published under that authority, with an effective date in mid 2025.
| Drug or analyte | Initial test cutoff (ng/mL) | Confirmatory test cutoff (ng/mL) |
|---|---|---|
| Marijuana metabolite, delta 9 THC | 4 | 2 |
| Cocaine and benzoylecgonine | 15 | 8 (each) |
| Codeine and morphine | 30 | 15 (each) |
| 6 acetylmorphine (heroin marker) | 4 | 2 |
| Hydrocodone and hydromorphone | 30 | 15 (each) |
| Oxycodone and oxymorphone | 30 | 15 (each) |
| Phencyclidine (PCP) | 10 | 10 |
| Amphetamine and methamphetamine | 50 | 25 (each) |
| MDMA and MDA | 50 | 25 (each) |
A few things stand out in that table. The THC cutoff of 4 ng/mL on the screen is intentionally set to catch active use while limiting the chance that passive exposure to smoke produces a nonnegative result. The opioid rows split into pairs, codeine with morphine, hydrocodone with hydromorphone, oxycodone with oxymorphone, because oral fluid picks up the parent opioid and its immediate metabolite together rather than a single marker. PCP is the one analyte where the screening and confirmatory cutoffs match, set at 10 ng/mL on both tests. Because HHS can revise this panel through an annual notice rather than a full rulemaking, employers running a federally regulated program should check the current Federal Register notice each year rather than assume a table stays fixed indefinitely.
Where the DOT oral fluid rule actually stands
The Department of Transportation published a final rule adding oral fluid as an authorized alternate specimen under 49 CFR Part 40 for its regulated modes, including FMCSA, FAA, FRA, and FTA covered employers. That rule became effective in June 2023. It did not make oral fluid mandatory. It made oral fluid an option employers can choose alongside urine testing, once the infrastructure to support it exists.
That infrastructure has been the holdup. Part 40 requires at least two HHS certified laboratories capable of oral fluid testing before any DOT regulated employer can use the method, because a split specimen has to be available for testing at a second, independent lab if a donor requests it. As of the most recent DOT rulemaking on this topic, no laboratory has yet received that HHS certification for oral fluid, so oral fluid testing is still not an option any DOT regulated employer can actually use for a Part 40 test.
DOT has continued to refine the rule while it waits on lab certification. A further amendment to Part 40 addressed what collectors and employers do in the gap, updated some terminology, and set out a transition period once certification happens. Once HHS certifies a second oral fluid laboratory, the rule gives employers a defined window during which they may continue directly observed urine collections in situations that would otherwise require oral fluid, before oral fluid becomes the required method in those specific circumstances. Employers with safety sensitive, federally regulated positions should treat oral fluid as not yet operational for DOT purposes and continue running compliant urine collections until their consortium or testing provider confirms certified oral fluid laboratory capacity exists.
How rapid, instant oral fluid device cutoffs differ from the federal table
The HHS table above governs federal workplace testing programs and will govern DOT testing once oral fluid becomes available there. It does not automatically govern every oral fluid device sold for non regulated workplace use. A private employer running a non DOT program can choose an oral fluid device cleared for over the counter or point of care use, and that device's screening cutoffs are set by its manufacturer as part of its regulatory clearance, not by the HHS Mandatory Guidelines.
In practice, many rapid oral fluid devices marketed to employers are built with cutoffs close to, or aligned with, the federal panel, because manufacturers want a device that behaves consistently with laboratory confirmation and with what employers already expect from urine cup cutoffs. But alignment is not guaranteed, and it can vary by analyte and by manufacturer. Some rapid devices use a single combined cutoff for an opioid pair rather than the two paired cutoffs HHS specifies. Some panels skip an analyte the federal table includes, or add one it does not. This is exactly why the cutoff level printed on a device insert, not the HHS table, is the number that governs how that specific device performs, and why a laboratory confirmation result on a nonnegative screen is what an employer and a Medical Review Officer should rely on for any adverse action, never the screening device alone.
Detection windows, and why oral fluid is not just a faster urine test
Oral fluid detects the parent drug because it forms through passive diffusion of drug directly from the bloodstream into saliva, largely independent of liver metabolism. Urine testing instead targets metabolites the body produces after the liver processes a drug. That distinction is the reason oral fluid tends to have a shorter detection window than urine for the same use, often described in the toxicology literature as recent use, on the order of a day or two for most drug classes, rather than the several day window urine can show for some substances. It also means oral fluid is less useful for detecting use from several days earlier and more useful for confirming whether someone used a substance close to the time of collection, which is part of why it fits post accident and reasonable suspicion testing well.
Collection conditions affect oral fluid results more than they affect urine. Recent food, mouthwash, or smoking close to collection can affect an oral fluid specimen's pH and volume, which is one reason collectors are trained to have a donor avoid eating, drinking, or using tobacco for a period before collection and to use a device with a built in volume adequacy indicator.
What employers should ask a supplier before switching
| Question to ask | Why it matters |
|---|---|
| Does the device cutoff match the HHS panel for each analyte, or does the insert list different numbers | Determines whether device results will read consistently with any lab confirmation |
| Is the device CLIA waived for the intended use setting | Point of care use outside a certified lab generally requires a CLIA waived categorization |
| Which analytes does the panel actually cover, and which pairs are combined into one line | Panels vary in whether they separate or combine opioid pairs and other analyte groups |
| What laboratory does confirmatory testing on nonnegative screens, and is it HHS certified | Confirmation and MRO review are what make a result defensible, not the screen alone |
| Is this program subject to DOT Part 40 | Oral fluid is not yet an available method for DOT regulated testing, regardless of device marketing |
| What is the specimen volume adequacy indicator, and what happens on a quantity not sufficient result | Oral fluid collections fail for insufficient volume more often than urine collections do |
Frequently asked questions
What is a cutoff level in oral fluid drug testing?
It is the concentration of a drug or marker, in nanograms per milliliter of undiluted oral fluid, that a specimen must reach to be reported nonnegative on a screening test and then again, usually at a lower threshold, on a laboratory confirmatory test.
What are the current HHS cutoff levels for oral fluid testing?
HHS publishes an authorized panel with paired initial and confirmatory cutoffs for marijuana, cocaine, opioids including codeine, morphine, hydrocodone, hydromorphone, oxycodone, and oxymorphone, PCP, and amphetamine type stimulants including MDMA and MDA, as shown in the table above. HHS can revise this panel through an annual Federal Register notice, so the current notice is the authoritative source.
Is oral fluid drug testing available for DOT regulated safety sensitive employees yet?
Not yet. DOT authorized oral fluid as an alternate method under 49 CFR Part 40, but the rule requires at least two HHS certified oral fluid laboratories before any employer can use it, and no laboratory has received that certification as of the most recent DOT rulemaking on the subject. DOT regulated employers should continue compliant urine testing until a consortium or testing provider confirms certified capacity exists.
Why do rapid oral fluid test cutoffs sometimes differ from the HHS federal cutoffs?
The HHS table governs federal and, eventually, DOT regulated testing. A device sold for non regulated workplace or point of care use is cleared with cutoffs its manufacturer sets, which may or may not match the federal panel for every analyte. Employers should check a device's insert rather than assume it mirrors the federal table.
How long can drugs be detected in oral fluid compared to urine?
Oral fluid generally shows a shorter detection window than urine for the same use because it detects the parent drug transferred from blood rather than metabolites the liver produces over time. That makes oral fluid better suited to confirming recent use and less suited to detecting use from many days earlier.
What should an employer ask a supplier before adding oral fluid to a testing program?
Confirm the device's cutoffs and analyte list against the HHS panel, confirm its CLIA waiver status for the intended setting, confirm which laboratory performs confirmatory testing and that it is HHS certified, and confirm whether the program is subject to DOT Part 40, since oral fluid is not yet an option there.
Related reading
- How Far Back Does a Mouth Swab Drug Test Go?
- Instant Drug Test Cups vs Lab Based Testing: Which to Buy
American Screening Corporation supplies oral fluid drug test devices for employers building or updating a testing program.
Sources
- Mandatory Guidelines for Federal Workplace Drug Testing Programs, Oral Fluid (Federal Register, HHS)
- Mandatory Guidelines for Federal Workplace Drug Testing Programs, Authorized Testing Panels (Federal Register, HHS)
- Procedures for Transportation Workplace Drug and Alcohol Testing Programs, Addition of Oral Fluid Specimen Testing (Federal Register, DOT)
- Procedures for Transportation Workplace Drug and Alcohol Testing Programs (Federal Register, DOT)
- 49 CFR Part 40, Procedures for Transportation Workplace Drug and Alcohol Testing Programs (eCFR)
- Interpretation of Oral Fluid Tests for Drugs of Abuse (National Institutes of Health, PMC)
This article is general information for employers and is not legal or medical advice. Testing programs subject to DOT or state rules should confirm current requirements with counsel or a compliance consortium before making policy changes.
