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Module CC-06 · Version 1.0

Thyroid Testing as a Pattern

A TSH result comes back suppressed with no free T4 measured yet. The pattern-recognition framework for TSH, free T4, total T4/T3, and thyroid antibody results covers classifying primary versus central hypo- and hyperthyroid directions, recognizing when total and free hormone can legitimately disagree, and knowing when biotin, heterophile antibodies, macro-TSH, or nonthyroidal illness should stop a diagnostic statement rather than support one.

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Who this module is for

Clinical laboratory scientists and students working toward independent bench sign-off in clinical chemistry, who already have the CC-05 endocrine feedback background.

Learning objectives

  • Classify common TSH/free T4 pattern directions as primary hypothyroid, primary hyperthyroid, or central hypothyroid signature
  • Explain why total and free hormone results can differ even when the axis is working correctly
  • Identify biotin, heterophile antibodies, macro-TSH, nonthyroidal illness, pregnancy, and medication effects as possible confounders and choose a defensible next laboratory action

How completion works

Mark every required section done and answer every knowledge check in those sections correctly. The final save completes the module automatically.

Sources

15 sources

  1. 1. American Thyroid Association. "Thyroid Function Tests." https://www.thyroid.org/thyroid-function-tests/. Accessed 2026-08-16.

    Source note · professional society guidance

  2. 2. American Thyroid Association. "How to Order Thyroid Function Tests." https://www.thyroid.org/wp-content/uploads/2026/01/ATA-Thyroid-Function-Tests.pdf. Accessed 2026-08-16.

    Source note · professional society guidance

  3. 3. American Thyroid Association-commissioned review. "Thyroid Stimulating Hormone and Thyroid Hormones (Triiodothyronine and Thyroxine): An American Thyroid Association-Commissioned Review of Current Clinical and Laboratory Status." Accessed 2026-08-16.

    Source note · peer-reviewed literature

  4. 4. Garber JR, Cobin RH, Gharib H, et al. "Clinical Practice Guidelines for Hypothyroidism in Adults: Cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association." Thyroid 2012;22(12):1200-1235.

    Source note · professional society guidance

  5. 5. American Thyroid Association. "Accuracy and Reproducibility" (laboratory services library, biotin interference statement). https://www.thyroid.org/professionals/laboratory-services-library/accuracy-and-reproducibility/. Accessed 2026-08-16.

    Source note · professional society guidance

  6. 6. American Thyroid Association. Clinical Thyroidology for Patients, Vol 11 Issue 12, p.3-4. https://www.thyroid.org/patient-thyroid-information/ct-for-patients/december-2018/vol-11-issue-12-p-3-4/. Accessed 2026-08-16.

    Source note · professional society guidance

  7. 7. Alexander EK, Pearce EN, Brent GA, et al. "2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum." Thyroid 2017;27(3):315-389.

    Source note · professional society guidance

  8. 8. Favresse J, Burlacu MC, Maiter D, Gruson D. "Interferences With Thyroid Function Immunoassays: Clinical Implications and Detection Algorithm." Endocrine Reviews 2018;39(5):830-850.

    Source note · peer-reviewed literature

  9. 9. NCBI Bookshelf (Endotext). "Assay of Thyroid Hormone and Related Substances." https://www.ncbi.nlm.nih.gov/books/NBK279113/. Accessed 2026-08-16.

    Source note · peer-reviewed literature

  10. 10. NCBI Bookshelf (Endotext). "The Non-Thyroidal Illness Syndrome." https://www.ncbi.nlm.nih.gov/sites/books/NBK285570/. Accessed 2026-08-16.

    Source note · peer-reviewed literature

  11. 11. NCBI Bookshelf (Endotext). "Evaluation of Thyroid Function in Health and Disease." https://ncbi.nlm.nih.gov/books/NBK285546/. Accessed 2026-08-16.

    Source note · peer-reviewed literature

  12. 12. Jonklaas J, Bianco AC, Bauer AJ, et al. "Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement." Thyroid 2014;24(12):1670-1751.

    Source note · professional society guidance

  13. 13. Code of Federal Regulations. 42 CFR 493.1291, "Standard: Test report." eCFR, current text retrieved 2026-08-16.

    Source note · federal guidance

  14. 14. Clinical and Laboratory Standards Institute. EP07, "Interference Testing in Clinical Chemistry," 3rd edition. https://clsi.org/shop/standards/ep07-plus/.

    Source note · consensus standard

  15. 15. "Thyroid-Stimulating Hormone Immunoassay Interference Presenting as Treatment-Refractory Hypothyroidism: A Case Report." https://pmc.ncbi.nlm.nih.gov/articles/PMC13266301/. Accessed 2026-08-16.

    Source note · peer-reviewed literature