Test Category: Specialist BiochemistryToxicology
Investigation Name:Clozapine
Alias or Abbreviation:CLZ
Accreditation:UKAS Accredited ISO15189:2022, on scope
Intro:
Clozapine is an atypical antipsychotic indicated for treatment-refractory schizophrenia that necessitates rigorous therapeutic drug monitoring to assess patient compliance, optimize efficacy and minimize toxicity. Quantitative measurement of plasma clozapine level is essential in patients with inadequate clinical response, suspected non-adherence, or when adverse side effects are observed. In the UK a significant percentage of patients treated with clozapine develop neutropenia or agranulocytosis.Toxicity may manifest as pronounced sedation, seizures, and cardiovascular disturbances such as arrhythmias, hypotension, or even myocarditis, while anticholinergic effects may also be evident.
The ratio of clozapine to its active metabolite norclozapine provides further insight, facilitating precise dose adjustments but is influenced by several clinical and pharmacological factors including non-adherence, smoking status, age, sex, concomitant medications, genetic variations and inflammatory status.
Pathology Laboratory:Toxicology Laboratory
Requestable Seperately?Yes
Units:µg/L
Minimum Sample Volume:2mL of EDTA blood or 1mL of plasma/serum.
Expected Turnaround Time:3 working days upon sample receipt
Test Code:CLZ
Sample Type:
A minimum of 2mL of EDTA whole blood or 1mL of plasma or serum is required.Complex Reference Range:Non-compliance, suboptimal dose: <350µg/L
Maximum drug efficacy: 350 - 600µg/L
Increased risk of side effects: >600µg/L
Referred to Another Laboratory?No
Storage Requirements:Samples should be stored at 4°C and sent to the laboratory at ambient temperature using the normal postal system.
Posting Address / Requirements:Sandwell Health Campus
Specialist Chemistry,
Pathology Department,
Lyndon,
B71 4HJ
NPEX / PDF Reporting Available:NPEX and PDF reporting available.
EQA Scheme:The laboratory is enrolled on an EQA scheme for Therapeutic Drugs with LGC Standards PT schemes and samples are received monthly for this.
Further information: A trough sample is required pre-dose or a minimum of 12 hours post-dose.
Lead Contact Details:Hayley Sharrod-Cole, Consultant Clinical Scientist
Email: hayley.sharrod-cole@nhs.net
Email Address For Chasing Results:rwh-tr.bcpsspecialistchemistryenquiries@nhs.net
Methodology:Analysed using HPLC-UV.
Site Sample Tested:City Health Campus
Cost:Please email: bcpspathology.info@nhs.net for further details
Contact Number:0121 507 4138
