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What is being tested?

The plasma paracetamol (or acetaminophen) concentration is being measured.

How is it used?

The plasma paracetamol concentration is used to establish a diagnosis of paracetamol over dosage and to help decide on the need for treatment.

When is it requested?

Only when paracetamol over dosage is a possibility.

What does the result mean?

The plasma paracetamol concentration at a known time point between 4 and 15 hours after a single overdose has been taken, indicates the likelihood of liver damage developing after 2 or 3 days. This test therefore helps the doctor decide on the need for antidotal treatment to minimise the risk of such damage occurring.

Is there anything else I should know?

Taking as few as ten to twenty 500 milligram paracetamol tablets at once can cause serious, possibly fatal liver damage 2-4 days afterwards unless antidotal treatment is given within 8 hours. It is likely that there will be no symptoms of poisoning for 24-36 hours after taking the paracetamol even if a potentially fatal dose has been ingested. If paracetamol has been taken above the recommended dose you should seek medical help as soon as possible.


There is increased risk of liver injury with an overdose if persons are malnourished for any reason or alcoholic or if fasting for more than a day.

Common questions

  • Is paracetamol dangerous if used appropriately?

Paracetamol is one of the safest, most effective drugs known if used at the recommended dose and dose interval.


  • Can paracetamol poisoning be treated at home?

No, if paracetamol poisoning is suspected, the patient should be taken to hospital immediately.

Last Updated: Thursday, 1st June 2023

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