rovides ustekinumab drug concentration and anti‐ustekinumab antibodies in order to optimize treatment and facilitate clinical decision‐making. This assay may be helpful in any patients on ustekinumab therapy for Crohn's disease, psoriasis, or other autoimmune conditions. Limitations Drug concentration should be interpreted with confirmation of specimen collection timing. Non‐trough concentrations may be misleading. Trough blood collection (just before or within 24 hrs. of next dose) is suitable because target ranges and therapeutic cut‐offs have been established in clinical studies using trough concentration. The drug half‐life should be taken into consideration when interpreting results from non‐perfect trough collections. Some primary non‐responders have inadequate clinical response despite adequate trough levels. As with other biologics, the optimal ustekinumab concentration depends upon patient‐specific factors including co‐morbidities, disease and desired therapeutic endpoint. Positive anti‐ustekinumab antibodies should be interpreted in the context of the concomitant free ustekinumab drug level. High serum biotin concentrations in patients taking biotin supplements may cause an interference in this assay. Patients may be advised to stop biotin consumption at least 72 hours prior to sample collection.
Specimen Type
Blood
Container
Gold Top Tube
Collection Instructions
Container/Tube: Gold Top Tube or Red Top Tube Specimen: 2 mL serum ( 1 mL min) Transport Temperature: Refrigerated Collection: Allow a minimum clotting time of 30 to 60 minutes with serum separation within 2 hours of collection.
Transport Instructions
Specimen Stability
14 Days Room Temperature 14 Days Refrigerated 14 Days Frozen
