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HelpTest Code GUSAB Guselkumab Antibodies, Serum
Specimen Required
Only orderable as part of profile. For more information see GUSAP / Guselkumab Quantitation with Antibodies, Serum.
Patient Preparation: For 12 hours before specimen collection, patient should not take multivitamins or dietary supplements (eg, hair, skin, and nail supplements) containing biotin (vitamin B7).
Supplies: Sarstedt Aliquot Tube 5 mL (T914)
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.6 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.
Secondary ID
623122Useful For
Evaluation of patients with loss of response to guselkumab, with recurrence of symptoms, or low or undetectable serum guselkumab measured at trough
Method Name
Only orderable as part of profile. For more information see GUSAP / Guselkumab Quantitation with Antibodies, Serum.
Electrochemiluminescent-Bridging Immunoassay (ECLIA)
Specimen Type
SerumSpecimen Minimum Volume
Serum: 0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 28 days |
| Frozen | 28 days | |
| Ambient | 14 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | Reject |
| Gross icterus | OK |
| Heat-treated specimens | Reject |
Reference Values
Only orderable as part of profile. For more information see GUSAP / Guselkumab Quantitation with Antibodies, Serum.
Antibodies to guselkumab
<9.8 ng/mL
Interpretation
The presence of detectable anti-guselkumab antibodies may be associated with increased guselkumab clearance and lower circulating concentrations of guselkumab in serum. Low trough concentrations of guselkumab may be correlated with loss of response to the drug.
Method Description
Testing for antibodies to guselkumab is accomplished using a laboratory-developed immunoassay.(Unpublished Mayo method)
Day(s) Performed
Thursday
Report Available
2 to 8 daysSpecimen Retention Time
14 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
83520
LOINC Code Information
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 623122 | Guselkumab Ab, S | In Process |
| 623291 | GUSAB Interpretation | 77202-0 |