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HelpOrderable Name GUS Guselkumab, Serum
Ordering Guidance
Therapeutic drug monitoring of guselkumab may be useful when assessing response to therapy is difficult or when patients need to be above a certain therapeutic concentration to improve the odds of a clinical response for therapy optimization, dose increases, or de-escalation or discontinuation of therapy.
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL Serum
Collection Instructions:
1. Draw blood immediately before next scheduled dose (trough specimen).
2. Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.
Useful For
Assessing the response to guselkumab therapy
Assessing the need for dose escalation
Evaluating the potential for dose de-escalation or discontinuation of therapy
Monitoring patients who need to be above a certain guselkumab concentration to improve the odds of a clinical response for therapy optimization
Method Name
Liquid Chromatography Mass Spectrometry (LC-MS)
Specimen Type
SerumSpecimen Minimum Volume
Serum: 0.25 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 28 days |
| Frozen | 28 days | |
| Ambient | 7 days |
Reject Due To
| Gross hemolysis | OK |
| Lipemia | Reject |
| Gross icterus | OK |
Reference Values
Lower limit of quantitation = 0.5 mcg/mL
Day(s) Performed
Wednesday
Report Available
2 to 9 daysCPT Code Information
80299
Testing Algorithm
For information see Ulcerative Colitis and Crohn Disease Therapeutic Drug Monitoring Algorithm.
Special Instructions
Forms
If not ordering electronically, complete, print, and send Gastroenterology and Hepatology Test Request (T728) with the specimen.