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Beaumont Laboratory

Interferon Beta, IgG

NabFeron, Interferon Blocking Ab , Interferon-Beta, IgG, FOCUS #20358, EPIC: LAB6526, SOFT: XINTB


Collect specimen at least 8 hours after Interferon injection. The specific drug being used to treat the patient must be provided with the patient requisition (i.e. Avonex, Rebif, Betaseron).

Specimen Collection Criteria

Collect (preferred specimen): One Gold-top SST tube.
Also acceptable: One plain Red-top tube.

Physician Office/Drawsite Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 1.5 mL serum, refrigerated (2-8°C or 36-46°F). (Min: 0.5 mL)

Rejection Criteria

  • Specimens not collected and processed as indicated.


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 7 days
Refrigerated (2-8°C or 36-46°F): 14 days
Frozen (-20°C/-4°F or below): 30 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Sendout Laboratory with any questions.


Sent to Focus Diagnostics, San Juan Capistrano, CA.


Results available in 2-9 days.

Reference Range

Less than 4.0 Units.

Test Methodology

Multi-Analyte Immunodetection (MAID).

Clinical Utility

Some multiple sclerosis patients receiving recombinant interferon-beta (IFNb) develop IFNb-specific antibodies that may block the therapeutic effect of the treatment. This assay screens for IgG antibodies capable of binding to IFNb; all samples with detectable IFNb binding antibodies will reflex to Interferon-beta Neutralization Assay (Focus Unit Code 20468) for an additional charge.

CPT Code

83520 (86382, if reflexed).

Test Codes


Last Updated


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This directory currently reflects information only for specimens collected and/or processed at the Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.