Natalizumab and Anti-Natalizumab Antibody, DoseASSURE™ NTZ

CPT: 80299; 82397
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  • Anti-alpha4-integrin inhibitor
  • biologic therapeutic drug monitoring (TDM)
  • biological monitoring
  • immunogenicity testing
  • Tysabri drug and antibody testing

Expected Turnaround Time

10 - 14 days

Specimen Requirements




2 mL

Minimum Volume

1 mL (Note: This volume does not allow for repeat testing.)


Red-top tube or gel-barrier tube


Allow a minimum clotting time of 30 to 60 minutes with serum separation within 2 hours of collection. Send serum in a plastic transport tube. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.

Storage Instructions

Refrigerate or freeze.

Stability Requirements



Room temperature

14 days


14 days


14 days

Freeze/thaw cycles

Stable x6

Test Details


Provides natalizumab drug and anti-natalizumab antibody concentrations for pharmacokinetic and immunogenic assessment to optimize treatment. This test may be helpful in any patient on natalizumab therapy for multiple sclerosis, Crohn's disease or other conditions.

In the presence of anti-natalizumab antibodies, the natalizumab level reflects the free antibody-unbound drug level.

This anti-natalizumab antibody assay is drug tolerant.


Electrochemiluminescence Immunoassay (ECLIA)


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
505510 Natalizumab Drug + Antibody 505507 Natalizumab Drug Level ug/mL Pending
505510 Natalizumab Drug + Antibody 505508 Anti-Natalizumab Antibody ng/mL Pending

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