Diagnosis
	The diagnosis of subclinical hypothyroidism is quite straightforward: a normal serum fT4 and a moderately high TSH level establish the diagnosis. Serum fT3 is usually normal, and so fT3 estimations do not add much to the diagnosis. Of course, a drug- induced increase in TSH should be ruled out. A slightly abnormal serum TSH value should be confirmed by a second estimation later, since it may be transient or due to drug administration. These tests should be requested in all middle-aged and elderly persons, and especially those with symptoms and findings possibly associated with mild hypothyroidism, such as tiredness, hypercholesterolemia etc. However, since "subclinical" by definition excludes the presence of obvious clinical symptoms and signs, and since this condition is quite prevalent, the question arises whether all persons, at least from an age and up, should be screened for a mild thyroid failure. Weetman (12) does not recommend screening of all the healthy adult population, whereas Danese and his co-workers13 claim that screening is cost-effective and should be considered in persons 35 years or older. This is even more important in more elderly females. The author’s practice is to ask for serum fT4, TSH and autoantibodies (AAB) in all females 35 years old and all males 50 years old, as discussed in more detail later.