Preferred Sample Type


Suitable Specimen Types

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

Sample Processing in Laboratory

Centrifuge and place in toxicology box in cold room.

Sample Preparation


Turnaround Time

5 working days

Sample Stability

4 ºC


General Information

Risperidone (Risperdal) is a benzisoxazole derivative with serotonergic and dopaminergic receptor antagonist properties. It is metabolised to the active metabolite 9hydroxyrisperidone. The drug has been used clinically since 1990 as an antipsychotic agent. It is supplied as the free base in 0.5 – 6 mg tablets and a 1 mg/mL solution for oral administration. Daily oral doses for adults range from 2 – 6 mg. The adverse effects associated with risperidone therapy include dizziness, somnolence, nausea, orthostatic hypotension, anxiety, headache and extrapyramidal symptoms. Hepatitis, tardive dyskinesia and neuroleptic malignant syndrome have been reported. Serotonin syndrome may occur when the drug is used with a SSRI.

This assay measures both risperidone and the metabolite, 9hydroxy risperidone.

Patient Preparation

For therapeutic monitoring purposes, a trough (before dose) sample should be taken.


Please avoid use of gel seperatror (yellow top) tubes.

Analysed by LC-MS/MS

Reference Range

Therapeutic concentrations of risperidone range between 10 and 90 μg/L, and the total sum of risperidone and 9-hydroxyrisperidone range between 10 and 100 μg/L.


  • EQA Scheme?: Yes
  • EQA Status: LGC TDM

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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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