Type
Blood Testing
Biomarkers
8
Duration
15 min
A thyroid screening measuring TSH (thyroid stimulating hormone) with reflex testing of free T4 if TSH is found to be abnormal. This stepwise approach is the standard clinical protocol for efficient thyroid evaluation.
The thyroid gland is a small but enormously influential organ that sets the metabolic pace for virtually every cell in the body. Thyroid dysfunction — whether overactive (hyperthyroidism) or underactive (hypothyroidism) — can produce a wide range of symptoms including fatigue, weight changes, temperature sensitivity, mood disturbance, hair thinning, and altered heart rate. Because these symptoms are non-specific and overlap with many other conditions, thyroid function testing is one of the most commonly requested blood tests. OneDayClinic uses a clinically efficient stepwise protocol: TSH (thyroid stimulating hormone) is measured first as the most sensitive screening marker. TSH is produced by the pituitary gland and rises when thyroid output is insufficient, or falls when the thyroid is overproducing hormones. If TSH is within the normal range, thyroid function is considered adequate and no further testing is needed. If TSH is abnormal — either elevated or suppressed — free T4 (thyroxine) is automatically measured from the same blood sample to characterise the pattern. This reflex testing approach avoids the unnecessary cost of measuring free T4 when TSH is normal, while ensuring that abnormal results are immediately investigated further. The test is suitable for individuals experiencing unexplained fatigue, weight gain or loss, temperature sensitivity, or mood changes, and for those with a family history of thyroid disease who want to establish a baseline.
Key Details
- Method
- TSH with free T4 reflex
- Results
- Next business day
- Lab
- ISO 15189 certified
Who Is This For?
Thyroid screening, unexplained fatigue or weight changes, family history of thyroid disease, baseline thyroid assessment
What's Included
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).