Acetaminophen Blood Test (Paracetamol Level)
Reviewed
Also called: Acetaminophen level, Paracetamol level, Acetaminophen drug test
This test measures the amount of acetaminophen in your blood. Outside the U.S., it's called paracetamol.
Specimen: Blood (serum or plasma; method depends on the laboratory)
Urgent safety information
If you think you or your child has taken too much acetaminophen, or you notice early symptoms of an acetaminophen overdose, call 911 or go to the nearest emergency room.
Emergency numbers on this page are for the United States. Outside the US, call your local emergency number.
Why this test may be ordered
- A known or possible overdose
- Uncertain ingestion time or amount
- Symptoms or laboratory findings that could indicate medicine-related liver injury
Preparation and collection
You don't need any special preparations for 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.
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.
Understanding results
If a result or symptoms suggest an emergency, get emergency medical help right away.
If results show a high level of acetaminophen, you or your child may be at risk for liver damage and may need immediate treatment.
- High acetaminophen level: If results show a high level of acetaminophen, you or your child may be at risk for liver damage and may need immediate treatment. Limitation: The type of treatment will depend on how much excess acetaminophen is in your system. Next step: After you get your results, your provider may recommend other tests or treatment.
- Level being rechecked after a possible overdose: They may repeat this test every four to six hours to make sure you are out of danger. Limitation: Drinking alcohol while taking acetaminophen can increase your risk of liver damage. Next step: If you have questions about your results, talk to your provider.
- A time-dependent treatment nomogram is not appropriate for every exposure pattern.
- Unknown timing, repeated supratherapeutic use, delayed absorption, combination products, and liver injury require separate clinical assessment.
- Units and assay reporting differ; values must not be converted or compared casually.
What to do next
After you get your results, your provider may recommend other tests or treatment. If you have questions about your results, talk to your provider.
- Does the sample timing allow this concentration to be interpreted reliably?
- Is this an acute single ingestion or a repeated/unknown exposure pattern?
- Are repeat concentrations or liver-injury tests needed?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.
U.S. National Library of Medicine: Acetaminophen Blood Test (Paracetamol Level)