Let’s explore “25-hydroxyvitamin D, total — lab reference”

The test method and the reason for testing affect which cutoff your clinician uses.

Advanced lipoprotein testing. Ask your clinician to use the performing laboratory classification.

Method, units, and cutoffs vary. Dr. Purser to decide whether to retain.

Adult interval. Pregnancy and pituitary disease require different interpretation.

Binding abnormalities and severe illness may affect some free-hormone assays.

Useful in selected hyperthyroid states; not a sensitive stand-alone test for hypothyroidism.

No broadly accepted treatment target. Dr. Purser to define whether and how this is used.

The test method matters. Positive result supports thyroid autoimmunity but does not determine treatment alone.

The test method matters. Also affects thyroglobulin tumor-marker interpretation.

Ask your clinician to use the exact assay cutoff. Helpful in selected Graves disease questions.

This is not a general thyroid wellness target. It may be used for follow-up after certain thyroid conditions, alongside thyroid anatomy and antibody results.

Morning fasting collection is preferred when practical. Day-to-day variation is substantial.