Specimen Requirements

Container/Tube:

Prefered:  Green-top (lithium heparin) tube

Acceptable:  Gold-top serum gel tube, plain, red-top tube, or EDTA plasma

MInimum Specimen Volume: 8 µL plus a dead volume

Stability:  Separated samples stored at 2 – 8°C and analyzed within 8 days, 4 days at 20‑25 °C, and 12 months at ‑20 °C (± 5 °C). Freeze only once

Collection Instructions:

Note: 1. Anti-thyroxine antibodies will interfere with this assay.

2. Human anti-mouse antibodies or other heterophile antibodies may be present in patient specimens. This assay has been specially formulated to minimize the effects of these antibodies, however results from patients known to have these antibodies should be carefully evaluated.

3.  Venipuncture should occur prior to sulfasalazine and/or sulfapyridine administration due to the potential for falsely depressed results.