Preferred Sample Type


Suitable Specimen Types

  • Serum
  • Li Hep Plasma
0.2 mL (absolute minimum is 100 uL)

Sample Processing in Laboratory


Sample Preparation


Turnaround Time

3-5 days

Sample Stability

4 ºC


General Information

Carbamazpine (Tegratol) is an anticonvulsant drug which is used for the treatment of generalised grand tonic-clonic (grand mal) and patial (focal) seizures. It is also used for the prophylaxis of manic-depressive illness in patients unresponsive to lithium and for the treatment of diabetic nephropathy. Carbamazpine induces its own metabolism and therefore half-life is decreased by chronic administration. Dose may need be increased to maintain effect in the first month of treatment.

Side effects that may be seen at any dose but are related to higher concentrations include:

  • Dizziness
  • Uncoordinated movement
  • Sleepiness
  • Blurred or double vision
  • Nystagmus
  • A red itchy rash
  • Nausea
  • Diarrhoea
  • Constipation
  • Confusion

Carbamazepine can also sometimes cause liver function abnormalities, low blood sodium levels, a decrease in white blood cells (WBCs) or an increase in eosinophils (a type of WBC).

As CBZ concentrations can vary quite markedly across the dosage interval, isolated measurements can be difficult to interpret, and standardisation of sample timing is advisable for long term monitoring. Samples should be taken at trough drug levels by collecting a sample prior to the next dose of carbamazepine.

Patient Preparation



None Given

Reference Range

Therapeutic range: 4-12 mg/L

Source : Pathology Harmony Recommendations

Nystagmus, ataxia and drowsiness occur at levels above 12 mg/L and more serious toxicity above 15 mg/L.


  • EQA Status:


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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