Ustekinumab Level

Test Code

18218

CPT Codes
80299<br><strong>This test is not available for New York Patient testing</strong>

Preferred Specimen

0.5 mL serum

Minimum Volume

0.35 mL

Instructions

Collect serum immediately before the next scheduled dose (trough specimen)

Transport Temperature

Refrigerated (cold packs)

Specimen Stability

Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Moderate and gross hemolysis

Methodology
Immunoassay (IA)

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Set up: Tues, Thurs, Sat; Report available: 3-5 days

Clinical Significance

Ustekinumab is a therapeutic monoclonal antibody against a shared subunit of the pro-inflammatory cytokines IL-12 and IL-23. It is used to treat psoriasis as well as moderate to severe ulcerative colitis and Crohn's disease. Trough concentrations of ustekinumab correlate with the likelihood of clinical remission, but the role of routine monitoring is not clear. Target concentrations may depend on indication, induction vs. maintenance, dosing schedules, drug clearance, and other factors. Trough concentrations >0.6 mcg/mL may be associated with an optimal clinical response in psoriasis [1]. Maintenance trough concentrations between 1.0-4.5 mcg/mL may be associated with an increased rate of clinical remission in inflammatory bowel disease [2]. The reportable range is 0.1-10 mcg/mL. This assay may be used to measure approved ustekinumab biosimilars.

1. Elberdin L, Fernandez-Torres RM, Mateos M et al. Front Med 2022;9:1017323
2. Restellini S, Khanna R, Afif W. Inflamm Bowel Dis 2018; 24:2165-2172

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.