Vedolizumab Level and Anti-Vedolizumab Antibodies
Label Mnemonic: VEDO
Epic code: LAB8523
Downtime form: A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery
Commercial Mail-out Laboratory
5231 RCP
356-8593
Specimen(s):
Serum
Specimen Instructions:
Draw blood immediately before next scheduled dose.
Collection Medium:
Red top tube 5 mL (Clot Activator)
Minimum:
Preferred Minimum: 1.5 mL serum in red top tube
Absolute Minimum: 0.75 mL serum in red top tube
Turn Around Time:
7 working days upon receipt at reference laboratory
Reference Range:
Vedolizumab lower limit of quantitation: 2.0 mcg/mL
Interpretive Data:
Data in the literature with association of vedolizumab trough levels and improved outcomes is still scarce. The limit of quantitation of the test is 2.0 mcg/mL. In a retrospective Mayo Clinic study conducted from 2016-2017 with 171 patients (62% Crohn disease, 31% ulcerative colitis, and 7% indeterminate colitis), the median vedolizumab trough concentration was 15.3 mcg/mL. Minimum trough (immediately before next infusion) therapeutic concentrations of vedolizumab are expected to be above 15 mcg/mL.
Comments:
Useful For:
Assessing the response to therapy with vedolizumab
An aid to achieving desired trough serum levels of vedolizumab
Monitoring patient compliance

Cautions:
Patients actively undergoing therapy with both vedolizumab and nivolumab (extremely rare scenario) should not have their therapeutic vedolizumab concentration assessed using this test. If the patient has taken nivolumab in the past, they should wait for 4 weeks after therapy with nivolumab has ended before being tested for vedolizumab quantitation using this method.

The presence of high concentrations of vedolizumab might inhibit the antibodies to vedolizumab (ATV) assay yielding false-negative results. In patients with concentrations of vedolizumab greater than 15.0 mcg/mL, the presence of an ATV is of little clinical significance.

Clinical management decisions for patients receiving vedolizumab treatment should not be based solely on quantitation of vedolizumab and assessment of ATV if appropriate. Test results must be interpreted within the clinical context of the patient.
Methodology:
Vedolizumab is extracted from serum and measured by liquid chromatography (high-resolution accurate-mass, HRAM) mass spectrometry.

Testing for antibodies to vedolizumab is accomplished using a laboratory-developed immunoassay.
CPT Code:
83520 x2