Specimen Collection Manual and Test Catalog

0.75 mL serum; minimum 0.5 mL

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

Aliquot and transport refrigerated.

Refrigerated

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

Moderate and gross hemolysis

Anti-Stelara, IL12, IL23, Interleukin-12 and 23 inhibitor, Stelara level, Quest test code 18217

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.

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. It is not significantly immunogenic and only a small percentage of treated patients develop antibodies. However, in these patients, antibodies may be associated with lower trough levels of the drug. Results >2 AU/mL indicate the presence of anti-drug antibody.

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