Basal TSH Examination (2)	

	TSH is usually low in hypothyroidism secondary to pituitary disease, but in some patients, abnormally glycosylated and poorly active TSH is secreted and measured by RIA with levels up to 8 or even 10mu/l. Values above 5mu/l are usually indicative of some degree of thyroid failure, and in overt primary hypothyroidism, values may be in the range of 10–l00mu/l or higher. A normal TSH value excludes primary hypothyroidism, provided that the hypothalamopituitary axis is intact.