Test Code 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
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)
Reporting Name
Guselkumab, SSpecimen Type
SerumSpecimen Minimum Volume
0.25 mL
Specimen Stability Information
Specimen Type | Temperature | Time |
---|---|---|
Serum | Refrigerated (preferred) | 28 days |
Frozen | 28 days | |
Ambient | 24 hours |
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 daysPerforming Laboratory

Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
80299
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
GUS | Guselkumab, S | In Process |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
622837 | Guselkumab, S | In Process |