Risperidone (Risperdal) and 9-Hydroxyrisperidone
Use
The measurement of risperidone and its active metabolite, 9-hydroxyrisperidone, is crucial for therapeutic drug monitoring of patients on risperidone therapy. It aids in assessing patient compliance, optimizing dosing, and avoiding toxicity. Monitoring the combined total concentrations of risperidone and 9-hydroxyrisperidone is important for ensuring patient safety and efficacy of the treatment.
Special Instructions
Risperidone and its metabolite concentrations should be measured at steady state, typically achieved several days after a patient starts or modifies their dosage. Blood samples should be drawn just before the next scheduled dose to capture trough levels. Attention must be paid to the specific specimen collection requirements to avoid specimen rejection and ensure test accuracy.
Limitations
This test does not evaluate the pharmacogenetic variations that can affect risperidone metabolism. Interference by other medications or substances may affect the interpretation of the results. Also, improper specimen collection, including using gel tubes or insufficient volume, can lead to inaccurate results or test delays.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 55157-2
- 9393-0
- 9383-1
- 9394-8
Result Turnaround Time
3-7 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
3 mL
Minimum Volume
0.6 mL
Container
Green-top (sodium heparin) tube(s).
Collection Instructions
Draw blood in a green-top (sodium heparin) tube(s), plasma gel tube is not acceptable. Spin down and send 3 mL sodium heparin plasma refrigerated in a plastic vial.
Causes for Rejection
NA
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |
| Refrigerated | 7 days |
| Frozen | 180 days |