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Drug Screen for Cocaine (Hair)

Published: August 9, 2026Updated: August 16, 2026

This test detects traces of cocaine in your hair, helping doctors understand if you’ve used cocaine over a period of weeks to months.

Quick summary

["Hair drug testing reveals long-term substance use patterns beyond recent exposure."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
41021-7
Short code
Cocaine Hair Ql
Synonyms
Cocaine Hair Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Used

Hair testing is useful when doctors need to assess prolonged substance use, especially when recent urine or blood tests may not show current exposure. It can also be part of pre-employment, legal, or workplace safety evaluations.

How the Test Works

Cocaine and its metabolites are absorbed into your hair follicles over time. Hair samples are analyzed to detect these substances, typically using a sensitive laboratory method like chromatography or immunoassay.

What to Expect Before the Test

No special preparation is needed. You’ll provide a small hair sample, usually from the back of your head, where hair grows continuously. The test focuses on the entire hair shaft, not just recent growth.

What the Results Mean

A positive result indicates the presence of cocaine metabolites in your hair, suggesting past use. The length of detectable cocaine in hair varies by individual but can last months to years, depending on hair growth and metabolism.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is valuable for identifying long-term substance use patterns, supporting treatment planning, or addressing concerns in legal, employment, or family contexts. It complements other tests like urine or blood screens, which detect recent use.

Short name

Cocaine Hair Test

Frequently asked questions

Can I shower or wash my hair before the test?
No, avoid washing your hair for at least 24 hours before the test to prevent removing potential cocaine metabolites from your hair.
How long does it take to get results?
Results are typically available within 1 to 2 weeks, depending on lab processing times.
Does this test show if I’m currently using cocaine?
No, this test detects past use over weeks to months. For current use, urine or blood tests are more appropriate.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy