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Acetaminophen Level

What is an acetaminophen level test?

This test measures the amount of acetaminophen in the blood. Acetaminophen is one of the most common medicines used in over-the-counter pain relievers and fever reducers. It is found in more than 200 brand name medicines. These include Tylenol, Excedrin, Nyquil, and Paracetamol, which is commonly found outside the U. S. Acetaminophen is safe and effective when taken at the proper dose. But an overdose can cause serious and sometimes deadly liver damage.

Unfortunately, dosing mistakes are common. Reasons for this include:

  • Taking more than one medicine that contains acetaminophen. Many cold, flu, and allergy medicines contain acetaminophen. If you take more than one medicine with acetaminophen, you may end up taking an unsafe dose without realizing it
  • Not following dose recommendations. The adult maximum dose is generally 4000 mgs in 24 hours. But that may be too much for some people. So it may be safer to limit your dose to 3000 mgs per day. Children's dosing recommendations depend on their weight and age.
  • Giving a child an adult version of the medicine, rather than a version designed for children

If you think you or your child has taken too much acetaminophen, call your health care provider right away. You may need to be tested and treated in the emergency room.

Other names: acetaminophen drug test, acetaminophen blood test, Paracetamol test, Tylenol drug test

What is it used for?

The test is used to find out if you or your child has taken too much acetaminophen.

Why do I need an acetaminophen level test?

Your provider may order a test if you or your child has symptoms of an overdose. Symptoms may happen as soon as two to three hours after taking the medicine but can take as long as 12 hours to appear.

Symptoms in adults and children are similar and may include:

What happens during an acetaminophen level test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Will I need to do anything to prepare for the test?

You don't need any special preparations for an acetaminophen level test.

Are there any risks to an acetaminophen level test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

If results show a high level of acetaminophen, you or your child may be at risk for liver damage and may need immediate treatment. The type of treatment will depend on how much excess acetaminophen is in your system. After you get your results, your provider may repeat this test every four to six hours to make sure you are out of danger.

If you have questions about your results, talk to your health care provider.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about an acetaminophen level test?

Before you or your child take any medicine, read the label carefully. Make sure that you only use the recommended dose. Check the ingredient list to see whether the medicines contain acetaminophen, so that you don't take too much. Common medicines that contain acetaminophen include:

  • Nyquil
  • Dayquil
  • Dristan
  • Contact
  • Theraflu
  • Actifed
  • Mucinex
  • Sudafed

Also, if you drink three or more alcoholic beverages a day, ask your health care provider if it is safe to take acetaminophen. Drinking alcohol while taking acetaminophen can increase your risk of liver damage.


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The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.