Ustekinumab Quantitation with Antibodies, Serum
Use
This test is useful for evaluating patients for potential adverse drug responses by measuring trough levels of ustekinumab and its antibodies. It can aid in managing cases of loss or partial response, hypersensitivity reactions, and evaluating appropriate dosing during therapy initiation or reintroduction after a drug holiday. It also helps assess recurrence in conditions like inflammatory bowel disease (IBD) and acute infusion reactions.
Special Instructions
Blood should be drawn immediately before the next dose of drug administration. It is crucial to send the specimen with the Gastroenterology and Hepatology Test Request or Therapeutics Test Request forms if not ordering electronically.
Limitations
This test measures free ustekinumab and free antibodies to ustekinumab but not drug bound complexes. Ustekinumab concentrations above 1 mcg/mL may impair detection of antibodies to ustekinumab. Presence of rheumatoid factor might interfere with antibody detection, affecting results. The assay does not differentiate between biosimilar and the original product formulations.
New York Approved
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 87408-1
- 87409-9
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
0.5 mL
Minimum Volume
0.35 mL
Container
Serum gel or red top (plastic vial for submission)
Collection Instructions
Draw blood immediately before the next dose of drug (trough level). Centrifuge and aliquot serum into a plastic vial.
Causes for Rejection
Reject if heat-inactivated.
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 21 days |
| Frozen | 21 days |