Preferred Sample Type


Suitable Specimen Types

  • Serum
  • EDTA Plasma
  • Li Hep Plasma
50 ul of plasma or serum.

Specimen Transport


Sample Processing in Laboratory

Centrifuge and place in toxicology box in cold room.

Sample Preparation


Turnaround Time

3 working days

Sample Stability

4 ºC


General Information

Naproxen (Aleve, Anaprox, Naprosyn) is a propionic acid derivative, structurally related to fenoprofen, ibruprofen and ketoprofen, that has been used clinically since 1972 as an anti-inflammatory, analgesic and antipyretic agent. It is supplied as the free acid or sodium salt, sometimes in combination with other drugs, in 200 - 550 mg normal release tablets or capsules and a 25 mg/mL suspension. Adult daily doses range from 250 - 1500 mg and are typically administrated in 1 - 3 portions.

The adverse reactions most commonly associated with naproxen include nausea, abdominal pain, constipation, headache, dizziness, drowsiness, tinnitus and skin eruptions. Fixed drug eruption, pancreatitis and hepatitis have been reported. 

Patient Preparation

For TDM, sample should be taken prior to dose. If toxicity is suspected, take sample at earliest opportunity


Please avoid use of gel seperator tubes.

Reference Range

25 - 75 mg/L.



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The Trust Laboratories at Heartlands Hospital, Good Hope Hospital and Solihull Hospital were awarded UKAS (United Kingdom Accreditation Service) accreditation to the internationally recognised ISO 15189 standard in May 2015. For a list of accredited tests and other information please visit the test database
Tests not appearing on this scope are either under consideration or in the process of accreditation and so currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.

For further information contact Louise Fallon, Quality Manager, 0121 424 1235

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