Laboratory Test Information Guide

Details for Thioridazine and Metabolite, Serum/Plasma

Test Name: Thioridazine and Metabolite, Serum/Plasma
Alternate Name(s): Mellaril®
Laboratory: Core
Specimen Type: 5 mL Gold top Vacutainer tube

Avoid gel-separator tubes
Collection Information: Minimum volume required is 1 mL.
Test Schedule: Referred out Monday-Thursday
Turnaround time from when specimen
is received in testing laboratory:
10 days
Reference Range: Thioridazine steady-state serum concentration during chronic oral administration of 400 mg daily: 140 - 2600 ng/mL

Therapeutic steady-state concentrations may overlap levels associated with toxicity.

Mesoridazine therapeutic range: 100 - 1400 ng/mL
Effective Date:  
Revised Date: 2020-06-22
Critical Value: Toxic: Greater than 27 µmol/L
Interpretive Comments: See Phenothiazine Screen for Qualitative test on Urine sample.
Special Processing: Test is also available on gastric lavage and random urine samples.
Comments: Thioridazine is a phenothiazine for treating psychosis. Monitoring its level is important to optimize therapy, to avoid toxicity, and to assure compliance.
Method of Analysis: Gas Chromatography
Critical Information Required:  
Storage & Shipment: Store and send cold.

Specimen Stability:
Ambient: 8 days
Refrigerated: 8 days
Frozen: 1 year
System Codes: 
Referred To: Hospitals In-Common Laboratory Inc.

Questions? Comments? Contact Laura Gopaul