Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Font Size

Toxicology Tests

What To Think About

  • In general, urine tests are better than blood tests at finding drugs. Traces of a drug may remain in urine longer than in blood. Urine tests often can detect drug use within the last 5 days.
  • Saliva tests can detect drugs just as well as urine and blood tests do, and they are less invasive than blood tests. (This means they don't require a needle stick.) A saliva test can detect drugs used within the past day.
  • Tox screen results are not always accurate. Sometimes a test may not find drugs that have been taken (false-negative result). Or a test may find drugs when they have not been taken (false-positive result).
  • Trying to change test results by drinking large amounts of water or taking other substances can be dangerous. And it usually doesn't change the results.
  • A test result that shows drug use or abuse can have serious outcomes, such as arrest or job loss. But the test result may not be accurate. So a positive result should always be confirmed by at least two different test methods.
  • A standard tox screen can't detect inhalant abuse, when someone sniffs common household products to "get high." Such products include glues, nail polish remover, lighter fluid, spray paints, and cleaning fluids.
  • A breath test may be used to estimate blood alcohol level. To learn more, see the topic Self-Test for Breath Alcohol.

Other Works Consulted

  • Chernecky CC, Berger BJ (2013). Laboratory Tests and Diagnostic Procedures, 6th ed. St. Louis: Saunders.

  • Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.

  • Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.

  • U.S. Anti-Doping Agency (2011). Athlete Handbook. Available online:

  • World Anti-Doping Agency (210). Guidelines for Urine Sample Collection. Available online:

ByHealthwise Staff
Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Specialist Medical ReviewerR. Steven Tharratt, MD, MPVM, FACP, FCCP - Pulmonology, Critical Care Medicine, Medical Toxicology

Current as ofSeptember 9, 2014

1 | 2 | 3 | 4 | 5

WebMD Medical Reference from Healthwise

Last Updated: September 09, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

Hot Topics

WebMD Video: Now Playing

Click here to wach video: Dirty Truth About Hand Washing

Which sex is the worst about washing up? Why is it so important? We’ve got the dirty truth on how and when to wash your hands.

Click here to watch video: Dirty Truth About Hand Washing

Popular Slideshows & Tools on WebMD

disciplining a boy
Types, symptoms, causes.
Remember your finger
Are You Getting More Forgetful?
fruit drinks
Eat these to think better.
No gym workout
Moves to help control blood sugar.
acupuncture needle on shoulder
10 tips to look and feel good.
Close up of eye
12 reasons you're distracted.
birth control pills
Which kind is right for you?
embarrassed woman
Do you feel guilty after eating?
Epinephrine Injection using Auto-Injector Syringe
Life-threatening triggers.
woman biting a big ice cube
Habits that wreck your teeth.
pacemaker next to xray
Treatment options.
caregiver with parent
10 tips for daily life.

Pollen counts, treatment tips, and more.

It's nothing to sneeze at.

Loading ...

Sending your email...

This feature is temporarily unavailable. Please try again later.


Now check your email account on your mobile phone to download your new app.

Women's Health Newsletter

Find out what women really need.