What Does 10DSP/NO THC/PHN Mean on a Drug Test?

“10DSP/NO THC/PHN” is a lab code describing a specific drug-screening order: a 10-Drug Screen Panel (10DSP) that excludes marijuana (NO THC) and includes phencyclidine, commonly known as PCP (PHN). You might see this shorthand on a lab requisition, a results form, or an employer’s testing policy. The code tells you exactly which substances the lab is looking for and, just as importantly, which one it is deliberately ignoring. Understanding each piece of the abbreviation clears up what your results actually cover and what they leave out.

What Each Part of the Code Means

The abbreviation breaks into three components, each modifying the test order in a specific way:

10DSP: Ten-Drug Screen Panel. This is the base test, designed to detect ten categories of controlled substances in a single urine sample. A standard 10-panel typically covers amphetamines, barbiturates, benzodiazepines, cocaine metabolites, marijuana metabolites (THC), methadone, methaqualone or a similar sedative, opiates, phencyclidine (PCP), and propoxyphene. Labs sometimes swap one or two substances depending on the ordering physician’s needs, but the overall structure stays the same.
NO THC: The panel has been ordered without the THC (tetrahydrocannabinol) assay. Your sample will not be screened for marijuana or its metabolites. Even if you recently used cannabis, this test is not designed to detect it.
PHN: Phencyclidine is included. Some labs use “PHN” or “PCP” interchangeably in their order codes. Its presence in the abbreviation typically confirms that PCP remains on the panel even though THC has been removed, since both sometimes appear as optional line items that an ordering party can toggle on or off.

If you see this code on your paperwork, it means the lab ran or will run a broad panel but made a deliberate choice to skip marijuana testing while keeping PCP testing active. The rest of the substances on the standard 10-panel are still being screened.

Why THC Gets Removed From a Panel

Removing marijuana from a drug screen used to be unusual, but it has become increasingly common. The most straightforward reason is legalization. As more states and jurisdictions permit recreational or medical cannabis use, many employers have concluded that screening for a legal substance creates more problems than it solves. A positive THC result might disqualify an otherwise strong candidate whose off-hours cannabis use has no bearing on job performance. Some companies have formally revised their policies to exclude THC from pre-employment and routine panels, and the “NO THC” modifier is how that policy shows up in the lab order.

Medical marijuana programs add another wrinkle. In states that protect registered patients from employment discrimination based on their cannabis prescription, testing for THC could expose an employer to legal liability. Rather than navigate the patchwork of protections, some organizations simply drop THC from the panel altogether. Federal contractors and safety-sensitive industries regulated by agencies like the Department of Transportation (DOT) are a notable exception; those employers generally must follow federal drug-testing guidelines, which still include THC. So if your test says “NO THC,” you are almost certainly not in a DOT-regulated role.

There is also a practical consideration around false positives. Over-the-counter CBD products, hemp-derived supplements, and certain foods can occasionally trigger a preliminary positive for THC on an immunoassay screen. Removing THC from the panel sidesteps the administrative burden of chasing down those ambiguous results. For employers primarily concerned about substances like opiates, cocaine, and amphetamines, dropping THC simplifies the process without weakening it in areas they care about most.

What the Remaining Nine Substances Cover

With THC removed, the panel still casts a wide net. The specific substances vary slightly by lab, but a typical 10-panel minus THC screens for the following nine categories:

Amphetamines: Includes amphetamine, methamphetamine, and in many assays, MDMA (ecstasy). Prescription stimulants like Adderall will also trigger this assay.
Barbiturates: Older sedatives such as phenobarbital and butalbital. These are less commonly prescribed today but still tested for.
Benzodiazepines: Anti-anxiety medications including diazepam, alprazolam, lorazepam, and clonazepam.
Cocaine metabolites: Specifically benzoylecgonine, the primary metabolite the body produces after cocaine use.
Methadone: A synthetic opioid used in pain management and medication-assisted treatment for opioid dependence.
Methaqualone: A sedative rarely encountered today in clinical settings but still included on many legacy panels. Some labs substitute expanded opioid or synthetic-opioid assays in this slot.
Opiates: Naturally derived opioids such as morphine and codeine, and sometimes semi-synthetic opioids like hydrocodone and oxycodone depending on the assay’s specificity.
Phencyclidine (PCP): The “PHN” in your code. PCP is a dissociative drug that remains a standard panel target despite its relatively low prevalence in most populations.
Propoxyphene: A synthetic opioid that was withdrawn from the U.S. market in 2010 but persists on some panel configurations. Labs that have updated their panels may substitute a broader synthetic-opioid screen.

If you take a prescription medication that falls into any of these categories, the immunoassay will likely flag it as a preliminary positive. That does not automatically mean you fail the test. It means the result will move to a confirmation step where a medical review officer (MRO) evaluates whether your prescription explains the finding.

How the Screening and Confirmation Process Works

Drug tests are not a single pass. The standard workflow uses two distinct technologies in sequence. The first step is an immunoassay, a rapid antibody-based screening that can process many samples quickly. Immunoassays are designed to be sensitive: they are meant to catch anything that might be present, even at the cost of occasionally flagging substances that are structurally similar to the target drug. If the immunoassay comes back negative for every substance on the panel, the result is reported as negative and the process stops.

When an immunoassay flags a preliminary positive, the sample moves to confirmatory testing using a more precise instrument, typically gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS). These methods can distinguish the exact compound and its concentration, eliminating the false positives that immunoassays are prone to. A study comparing immunoassay screening with GC-MS confirmation found that GC-MS was used as the definitive method for confirming all positives from either of two common immunoassay platforms across multiple laboratories.¹ The same GC-MS methods have been developed and validated specifically for confirming marijuana, cocaine, opiates, amphetamines, methamphetamine, and phencyclidine against immunoassay results.²

For someone whose panel reads “10DSP/NO THC/PHN,” this two-step process applies to every substance on the remaining nine-category list. The practical implication: a preliminary positive is not a final answer. Only a confirmed positive that survives the GC-MS or LC-MS/MS step, and then review by an MRO, is reported to your employer or ordering party as a verified positive result.

Cross-Reactivity and Unexpected Positives

One of the most common sources of confusion in drug testing is the preliminary positive that shows up even though you have not taken the target drug. This happens because immunoassays detect drug classes based on molecular shape, and other compounds can be close enough in structure to trigger the antibody. The amphetamine assay is particularly notorious for this. A review of manufacturer cross-reactivity data found that ephedrine and pseudoephedrine, ingredients found in many cold and allergy medications, appeared in the cross-reactivity disclosures of over 80% of amphetamine immunoassay package inserts. Phentermine, a weight-loss medication, appeared in about two-thirds, and bupropion, a common antidepressant, showed up in 40% of inserts.³

For the opiate assay, poppy seeds are the classic offender: consuming a large amount of poppy-seed-containing food can produce enough morphine and codeine in your urine to trip the screen. Benzodiazepine immunoassays can cross-react with certain anti-inflammatory drugs. And the PCP assay, the “PHN” portion of your panel, has been reported to cross-react with dextromethorphan (a cough suppressant) and certain antihistamines at high doses.

None of these cross-reactivities result in a final positive, because the confirmatory GC-MS or LC-MS/MS step can distinguish the actual molecule in the sample. But they can cause delays and anxiety while you wait for the confirmation result. If you know you take a medication that could trigger a cross-reactive preliminary positive, inform the MRO proactively when the test is ordered. Having your prescription documentation ready speeds up the review.

Specimen Validity Checks That Run Alongside Your Panel

Whether your panel includes THC or not, the lab also runs a set of specimen validity tests on your urine sample to make sure it has not been tampered with, diluted, or substituted. These checks happen automatically and are separate from the drug assays themselves. The parameters typically include:

Temperature: Fresh urine should arrive at the collection site between 90°F and 100°F. A sample outside this range may signal substitution.
Specific gravity: Normal urine falls between 1.005 and 1.030. Readings outside this range suggest the sample was diluted with water or another fluid.
pH: Normal urine pH ranges from 4.5 to 8.0. Values outside that window may indicate chemical additives.
Creatinine: A waste product your kidneys excrete at a relatively steady rate. Low creatinine suggests the sample was heavily diluted.
Oxidants: Substances like bleach, hydrogen peroxide, or glutaraldehyde are sometimes used to adulterate a sample and interfere with drug detection. Federal guidelines flag nitrite levels above 200 micrograms per milliliter as suspicious.⁴

If any of these parameters fall outside their acceptable range, the lab may report the specimen as dilute, substituted, or invalid. A dilute specimen sometimes triggers a retest; a substituted or invalid specimen is treated more seriously and could be considered a refusal to test, depending on employer policy. Drinking large amounts of water before a test can inadvertently push creatinine and specific gravity below the threshold, so moderate hydration is a better strategy than chugging fluids.

When Oral Fluid Testing Replaces Urine

Not every drug test uses urine. Oral fluid (saliva) testing has grown in popularity because it is harder to adulterate and easier to collect under direct observation. If your employer opts for oral fluid instead of urine, the same panel concept applies: a 10-panel can be ordered with or without THC, and the same abbreviation structure may appear on the order form.

Detection rates do differ between the two specimen types, though. A study comparing paired oral fluid and urine collections found that cocaine was detected at roughly twice the rate in oral fluid compared to urine (about 16% versus 8%), while cannabinoids were detected at a somewhat lower rate in oral fluid than in urine (about 16% versus 20%). Opiates were also detected at slightly higher rates in oral fluid. Benzodiazepines, on the other hand, showed lower detection in oral fluid compared to urine.⁵ These differences mean that the specimen type can influence the likelihood of a detection for certain drugs, though neither method is categorically superior for all substances.

If your test was ordered as a urine screen, the “10DSP/NO THC/PHN” notation applies to a urine immunoassay with the standard confirmation pathway. If it was ordered as an oral fluid screen, the same panel logic holds, but the detection windows and sensitivities shift. Oral fluid testing generally detects more recent use (hours to a couple of days for most substances), while urine testing captures a wider window (typically a few days, though heavy chronic use of some substances can extend detection to weeks).

What Your Results Will Look Like

When your results come back from a “10DSP/NO THC/PHN” order, you will see each tested substance listed individually with a result next to it, usually “Negative” or “Positive.” THC will either be absent from the list entirely or appear with a notation like “Not Tested” or “Excluded.” A negative result across the board means none of the nine target substances were detected above their respective cutoff concentrations. A positive result for any substance means the immunoassay flagged it and the confirmatory test verified the presence of that specific drug or metabolite above the established threshold.

The cutoff concentrations vary by substance. For example, the standard immunoassay cutoff for amphetamines is typically 1,000 nanograms per milliliter, while the confirmation cutoff for amphetamine specifically is lower, usually 500 nanograms per milliliter. Cocaine metabolite cutoffs are generally set at 150 nanograms per milliliter for screening and 100 for confirmation. These thresholds are designed to avoid flagging trace environmental exposure while catching actual use. If your result is negative, it means your sample fell below all of these cutoffs for every substance tested.

One detail worth noting: a “NO THC” panel does not mean the lab cannot detect THC in your sample. It means the lab was not asked to look for it. If the same sample were later tested under a different order that included THC, the result could differ. The panel defines the scope of what gets reported, not the biological content of the sample. So if your employer later changes their policy and orders a full 10-panel retest, any substance present in sufficient quantity would show up, including THC.

Hair and Blood Panels Use Different Abbreviations

The “10DSP/NO THC/PHN” format is most common in urine and oral fluid testing. If you encounter hair or blood drug testing, the abbreviation conventions may differ even though the underlying panel logic is similar. Hair testing has a much longer detection window, often reaching back about 90 days, and is used less frequently in routine employment screening but more often in legal or forensic contexts. Blood testing, meanwhile, reflects very recent use (usually hours) and is primarily used in post-accident or impairment investigations rather than scheduled employment screens.

Hair panels are sometimes ordered as 5-panel, 9-panel, or 12-panel configurations, and THC exclusion is less common in hair testing because the longer detection window changes the interpretive context. A workplace study analyzing both urine and hair specimens found that cannabinoids and codeine were detected in hair samples even when urine screening results differed, reflecting the different detection pharmacology of each specimen type.⁶ If your drug test uses hair rather than urine, ask the ordering party which panel was selected and whether THC has been excluded, because you cannot assume the same modifiers apply across specimen types.