--- title: "how long does PCP stay in hair" description: "How long does PCP stay in hair? Hair drug tests detect PCP for months. Accurate SAMHSA-aligned lab testing. Call (877) 731-6362 for details." author: "AMH Nationwide" date: "2026-08-28" tags: ["how long does PCP stay in hair"] canonical: "https://amhnationwide.com/how-long-does-pcp-stay-in-hair/" last_updated: "2026-08-31" --- # how long does PCP stay in hair **By AMH Nationwide** | August 28, 2026 How long does PCP stay in hair? Hair drug tests detect PCP for months. Accurate SAMHSA-aligned lab testing. Call (877) 731-6362 for details. --- How long does PCP stay in hair? PCP can be detected in hair for up to 90 days or more after use, depending on hair length and growth rate. Hair drug tests capture PCP metabolites embedded in hair follicles, providing a long detection window compared to urine or blood. Factors like hair color and usage frequency affect detection. Call (877) 731-6362 for precise testing information. OVERVIEW ## How long does PCP stay in hair after use? PCP, or phencyclidine, incorporates into hair strands soon after ingestion, allowing for detection for typically up to 90 days after use. Hair grows at an average rate of about 1.3 centimeters per month, and standard drug panels analyze approximately 1.5 inches (3.8 cm) of hair closest to the scalp. This length corresponds to roughly a 90-day [detection window](https://amhnationwide.com/hair-follicle-drug-test-detection-window/), which is significantly longer than [urine](https://amhnationwide.com/urine-drug-testing/) or blood testing. Typical detection window: up to 90 days Hair analyzed: 1.5 inches from scalp Detection depends on hair length and growth rate Longer detection than urine (1-4 days) or blood (up to 24 hours) The 90-day period is an industry standard used by national labs including [Quest Diagnostics](https://www.questdiagnostics.com/), [LabCorp](https://www.labcorp.com/), Omega Labs, United States Drug Testing Labs, and ExperTox, all of which AMH Nationwide utilizes for sample analysis. This extended window is why hair testing is preferred for monitoring historical PCP use. SCIENCE ## How does PCP get into hair and how is it measured? PCP enters the hair follicle through the bloodstream during the hair’s active growth phase (anagen phase). The drug and its metabolites bind to the keratin matrix inside the hair shaft, becoming permanently incorporated as the hair grows out. This process allows hair to serve as a chronological record of drug exposure. Testing for PCP in hair involves sensitive methods like gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS). These techniques identify PCP metabolites at low picogram-per-milligram levels of hair, ensuring precise and reliable detection. PCP binds to the hair’s keratin during anagen phase Detection targets PCP metabolites, not just the parent drug Testing uses GC-MS or LC-MS/MS for high specificity Cutoff concentrations follow [SAMHSA](https://www.samhsa.gov/workplace/drug-testing) guidelines for hair analysis AMH Nationwide routes samples through its five national lab networks, all accredited by CAP and CLIA, ensuring that each sample undergoes rigorous quality control. Results reviewed by certified Medical Review Officers confirm accuracy before reporting. FACTORS ## What factors affect how long PCP stays in hair? Several factors influence PCP detection duration and concentration in hair samples. Hair color, texture, and cosmetic treatments can alter drug binding and retention. Darker hair with higher melanin content generally binds more PCP. Frequent or heavy PCP use results in higher concentrations, increasing detection likelihood. Environmental exposure to PCP does not typically cause a positive result because testing targets metabolites formed in the body, not external contamination. Hair color: more melanin can increase PCP binding Hair treatments (bleaching, dyeing) may degrade PCP concentrations Frequency and amount of PCP use impact detected levels External contamination is unlikely to cause false positives Certified Medical Review Officers evaluate each case considering these variables, ensuring that positive findings correlate with actual drug use rather than external factors or hair condition. LAB PROCESS ## How does AMH Nationwide test hair for PCP? AMH Nationwide does not collect samples directly but facilitates testing through a network of over 20,000 nationwide collection sites. Samples are sent to one of five national lab networks: Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, or ExperTox. Each lab follows SAMHSA-aligned protocols for hair drug testing, including PCP, using validated cutoff concentrations typically around 1 picogram per milligram of hair. Non-negative results undergo mandatory review by a certified Medical Review Officer to confirm the findings and interpret any medical explanations. Sample collection at 20,000+ nationwide sites Analysis performed at CAP- and CLIA-accredited labs SAMHSA-aligned cutoff levels for PCP detection Certified Medical Review Officer reviews all non-negative results AMH Nationwide provides the lab order and directs the requester to a collection site. No online ordering is available. Call (877) 731-6362 to arrange testing or request more information. ## Arrange Accurate PCP Hair Testing Today To schedule a hair drug test for PCP or get detailed information about detection windows and protocols, contact AMH Nationwide. Call (877) 731-6362 to speak with a testing specialist and find a nearby collection site. [Call (877) 731-6362](tel:+18777316362)[Contact Us](https://amhnationwide.com/contact-us/) COMPARISON ## How does hair testing for PCP compare to other sample types? Hair testing offers a much longer detection window than urine, blood, or saliva tests. Urine screening for PCP typically detects use within the past 3 to 7 days. Blood tests detect PCP only for up to 24 hours after use, while saliva tests detect even shorter windows. Hair testing can reveal PCP use over months, making it suitable for employment screening, court orders, or monitoring compliance with treatment or [probation](https://amhnationwide.com/hair-follicle-drug-test-probation/) conditions. | Test Type | Typical PCP Detection Window | | --- | --- | | Hair | Up to 90 days or longer | | Urine | 3 to 7 days | | Blood | Up to 24 hours | | Saliva | 1 to 2 days | REGULATORY ## What regulatory standards govern hair PCP testing? Hair drug testing for PCP is regulated by multiple agencies and standards. While the Department of Transportation (DOT) mandates urine testing for safety-sensitive roles under [49 CFR Part 40](https://www.transportation.gov/odapc/part40), hair testing is used mainly for non-DOT roles. SAMHSA provides cutoff guidelines for hair drug testing to ensure consistency and accuracy. Labs used by AMH Nationwide maintain accreditation from the College of American Pathologists (CAP) and Clinical Laboratory Improvement Amendments (CLIA), ensuring strict compliance with federal regulations and quality standards. DOT requires federally certified urine testing; hair testing is non-DOT SAMHSA hair testing cutoff for PCP is 1 pg/mg hair Labs must be CAP and CLIA accredited for hair testing Certified Medical Review Officers interpret all positive hair tests These regulatory frameworks guarantee that PCP hair testing results are defensible for employment decisions, legal proceedings, and clinical assessments. AMH Reviewed & Maintained By AMH Nationwide Customer Service AMH Nationwide is BBB A+ accredited and routes every order through Quest Diagnostics, LabCorp, Omega Labs, United States Drug Testing Labs, or ExperTox, all of which use multiple lab certification agencies and standards such as SAMHSA-aligned laboratory protocols, the ANSI National Accreditation Board for forensic testing and calibration, the College of American Pathologists (CAP), and Clinical Laboratory Improvement Amendments (CLIA). Every non-negative screen is reviewed by a certified Medical Review Officer as part of standard processing before a result is released, and chain-of-custody documentation is maintained on every collection. This page does not constitute medical or legal advice. **Last updated:** July 2026 You May Also Need [Nail Drug TestingNo head or body hair available? A 5-panel fingernail test covers a similar look-back window.Learn more →](https://amhnationwide.com/5-panel-fingernail-drug-test/)[ChildGuard: Environmental ExposureConcerned about a child or loved one? ChildGuard screens for exposure to drugs in their environment.Learn more →](https://amhnationwide.com/5-panel-hair-drug-test-environmental-exposure-childguard/)[Shorten the Detection WindowShortened options like 30 and 60 day hair panels are also available, useful when a urine test’s 1-3 day window is too short.Learn more →](https://amhnationwide.com/30-day-hair-drug-test/)[Hair ETG Alcohol TestAlso need alcohol testing? The hair ETG test screens for alcohol use, and can be added to the same collection.Learn more →](https://amhnationwide.com/etg-and-peth/) Frequently Asked Questions ## Common Questions Yes, hair testing can detect PCP after a single use because the drug and its metabolites incorporate into hair during growth. However, the concentration may be low and depends on timing relative to hair sample collection. Hair color influences PCP binding because melanin attracts drug molecules. Darker hair often retains higher drug levels than lighter hair, potentially affecting test sensitivity. Hair testing typically detects PCP about 5 to 7 days after use since the drug must reach the hair follicle and grow out to the sampled length. Chemical treatments like bleaching can reduce drug concentrations, possibly leading to false negatives. False positives are rare due to confirmation testing and MRO review. No, DOT regulations require urine testing under 49 CFR Part 40. Hair testing is used primarily for non-DOT roles and other legal or employment contexts. Using five national labs ensures broad geographic coverage, standardized testing protocols, and rapid turnaround times while maintaining rigorous quality through CAP and CLIA accreditation. Sources • [SAMHSA – Mandatory Guidelines for Federal Workplace Drug Testing Programs](https://www.samhsa.gov/workplace/drug-testing) • [U.S. DOT – 49 CFR Part 40 – Procedures for Transportation Workplace Drug and Alcohol Testing Programs](https://www.transportation.gov/odapc/part40) • [CDC – National Center for Health Statistics – Drug Use FastStats](https://www.cdc.gov/nchs/fastats/drug-use.htm) • [Quest Diagnostics – Employer Solutions, Hair Testing Methodology](https://www.questdiagnostics.com/) • [LabCorp – Occupational Testing Services](https://www.labcorp.com/) ## Ready to get started? AMH Nationwide provides the lab order and arranges collection nationwide. Every non-negative result reviewed by a certified Medical Review Officer. Call (877) 731-6362 or contact us. [Call (877) 731-6362](tel:+18777316362)[Contact Us](https://amhnationwide.com/contact-us/) --- **Need a drug, alcohol, HIV or STD test?** AMH Nationwide is a national lab testing agency operating since 2004, with more than 20,000 collection sites across the United States. Hair, urine, fingernail and blood testing, panels from 5 through 19, for individuals and employers. - Call: (877) 731-6377 - Find a collection site: https://amhnationwide.com/locations/ - Full page: https://amhnationwide.com/how-long-does-pcp-stay-in-hair/