Type
Blood Testing
Biomarkers
8
Duration
10 min
Results
48 hours
Core thyroid function panel measuring fT3, fT4, and TSH — the three markers needed to assess both thyroid hormone production and pituitary feedback. More informative than TSH alone for detecting subclinical thyroid states.
This panel measures the three primary thyroid function markers that together provide a complete picture of the hypothalamic-pituitary-thyroid axis. TSH alone can identify overt hypo- or hyperthyroidism, but the addition of free T3 and free T4 enables detection and classification of subclinical states that TSH screening misses or mischaracterises. TSH (thyroid-stimulating hormone) from the anterior pituitary is the most sensitive single marker for primary thyroid dysfunction. It rises in response to falling thyroid hormone levels and is suppressed when thyroid hormone is excessive. The reference range is approximately 0.4-4.0 mIU/L, though evidence suggests the optimal range for most adults is 0.5-2.5 mIU/L. Free T4 (thyroxine) is the predominant circulating thyroid hormone and the direct product of the thyroid gland. Only the free (unbound) fraction is metabolically active — total T4 is influenced by binding protein changes from pregnancy, oral contraceptives, liver disease, and genetic variation. Free T4 is the first marker to change in central (secondary) hypothyroidism, where TSH may be misleadingly normal. Free T3 (triiodothyronine) is the biologically active thyroid hormone, primarily produced by peripheral conversion of T4 via deiodinase enzymes. Discordant T3 and T4 levels can identify conversion disorders — for example, selenium deficiency impairs T4-to-T3 conversion and produces a pattern of normal T4 with low T3. This is also the pattern seen in non-thyroidal illness (sick euthyroid syndrome) during acute medical illness. The combination of all three markers allows classification into distinct clinical patterns: elevated TSH with low fT4 confirms primary hypothyroidism; suppressed TSH with elevated fT3 and/or fT4 indicates hyperthyroidism; mildly elevated TSH with normal free hormones identifies subclinical hypothyroidism. If autoimmune thyroid disease is suspected, the Schilddruese Gross panel adds TPO antibodies and TSH receptor antibodies for aetiological classification.
Key Details
- Biomarkers
- 3
- Results
- 1-2 days
- All-in price
- €64.03
Who Is This For?
Thyroid screening, fatigue investigation, weight changes, family history of thyroid disease, medication monitoring
What's Included
Preparation Required
No fasting required. Morning draw preferred as TSH follows a circadian rhythm with peak levels in early morning. Biotin supplements should be discontinued 48 hours before testing as they can interfere with immunoassay results.
Panel Categories
Biomarkers Tested
8The active form of thyroid hormone responsible for regulating metabolism, energy, and body temperature. Free T3 is converted from T4 in tissues and is three to four times more potent than T4.
The unbound, active form of the main thyroid hormone T4. Free T4 directly reflects thyroid gland output and is used alongside TSH to diagnose and monitor thyroid disorders.
Free triiodothyronine; high levels indicate hyperthyroidism, low levels hypothyroidism.
Free thyroxine; high levels indicate hyperthyroidism, low levels hypothyroidism.
A group of proteins in blood including antibodies (immunoglobulins), transport proteins, and enzymes. Elevated globulin can indicate chronic infection, inflammation, or blood cancers. Calculated by subtracting albumin from total protein.
An inactive form of T3 produced when the body converts T4. Elevated reverse T3 can occur during illness, stress, or caloric restriction and may indicate impaired thyroid hormone activation despite normal TSH levels.
Antibodies against thyroid peroxidase, an enzyme essential for thyroid hormone production. Positive TPO antibodies indicate autoimmune thyroid disease, most commonly Hashimoto's thyroiditis, even before symptoms or TSH changes appear.
The primary screening test for thyroid function. TSH is produced by the pituitary gland to regulate thyroid hormone production. High TSH indicates an underactive thyroid (hypothyroidism), while low TSH suggests an overactive thyroid (hyperthyroidism).
€64.03 all-inclusive (blood draw + processing fee included). No additional surcharges.
- Category
- Diagnostic
- Sample Type
- Blood (venous draw)
- Duration
- 10 min
- Results
- 48 hours