SPINA-GT is elevated in primary hyperthyroidism and reduced in both primary hypothyroidism and untreated autoimmune thyroiditis. It has been observed to correlate (with positive direction) to resting energy expenditure, resting heart rate, the colour Doppler ultrasound pattern and thyroid volume, and (with negative direction) to thyroid autoantibody titres, which reflect organ destruction due to autoimmunity. Elevated SPINA-GT in Graves' disease is reversible with antithyroid treatment. While SPINA-GT is significantly altered in primary thyroid disorders, it is insensitive to disorders of secondary nature (e.g. pure pituitary diseases).