Type
Blood Testing
Biomarkers
8
Duration
10 min
Results
3 days
A complete thyroid assessment measuring TSH, free T3, and free T4 — the three markers needed to properly evaluate thyroid function. Standard GP screening typically only includes TSH, which can miss subclinical thyroid dysfunction where TSH is borderline but the active hormones (T3/T4) are already abnormal. Thyroid disorders affect approximately 1 in 20 Australians and are 5-8 times more common in women.
The thyroid gland produces hormones that regulate metabolism, energy, body temperature, heart rate, mood, and cognitive function. Dysfunction — either overactive (hyperthyroidism) or underactive (hypothyroidism) — produces symptoms that overlap with dozens of other conditions, making it one of the most commonly missed diagnoses. TSH (thyroid-stimulating hormone) from the pituitary gland is the standard screening marker — elevated TSH suggests hypothyroidism, suppressed TSH suggests hyperthyroidism. However, TSH alone misses subclinical cases where the pituitary is compensating for early thyroid failure by producing more TSH, but free T3 and T4 are already declining. Free T4 (thyroxine) is the primary thyroid hormone produced in large quantities, while free T3 (triiodothyronine) is the active form that enters cells and drives metabolic effects. Poor T4-to-T3 conversion — which occurs with stress, inflammation, calorie restriction, and certain nutrient deficiencies — can cause hypothyroid symptoms even with normal TSH and T4. This panel is essential for anyone with fatigue, unexplained weight changes, cold sensitivity, hair loss, constipation, anxiety, or family history of thyroid disease. No fasting required, though morning collection is recommended for consistent TSH readings.
Key Details
- Markers
- 3 thyroid markers
- Beyond TSH
- Includes free T3 + T4
- Collection fee
- +A$20
Who Is This For?
Thyroid screening, fatigue, weight changes, cold sensitivity, hair loss, women's health, family history of thyroid disease
What's Included
Preparation Required
No fasting required. Morning blood draw recommended for consistent TSH measurement. If taking thyroid medication, test before your morning dose.
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).
- Category
- Diagnostic
- Sample Type
- Blood (venous draw)
- Duration
- 10 min
- Results
- 3 days