A lthough the cost-effectiveness of screening newborn babies for hypothyroidism using lter paper dried blood spot (DBS) specimens has been recognised worldwide, only recently has the technique been considered for screening other age groups. Primary hypothyroidism, for which every baby born in the US is screened, has a prevalence of 0.02% to 0.03% in newborn babies. 1 In adults, the incidence of primary hypothyroidism reported from the Whickham Survey from the UK was 4.1 per 1000 per year in women and 0.6 per 1000 per year in men.2 Previously unrecognised overt hypothyroidism in the general population has been reported to be approximately 1-2% in women and 0.1% in men.3,4 The risk of developing primary hypothyroidism increases with age, is greater in women than men at any age and is greater if tests for thyroid antibodies are positive or if the rise in serum thyroid-stimulating hormone (TSH) is above 2 mU/l. 5Another study suggested that 2.5% of women and 1.4% of men have undiagnosed overt hypothyroidism, and the prevalence of subclinical hypothyroidism was 17% for women and 14% for men. 6 Screening for primary hypothyroidism in adults was shown to be cost-effective when TSH was measured once every ve years after the age of 35 years, especially in women.7 Because the symptoms of hypothyroidism can be mistaken for medical and psychiatric diseases, as well as for general signs of ageing such as weakness, lethargy and fatigue, the diagnosis is often missed in older populations, as it is in newborn infants. 4 Several subsequent con rmatory studies have recommended screening with TSH for hypothyroidism in selected populations of adults. 4,[7][8][9] The American Thyroid Association, 10 the American College of Physicians, 11,12 and the National Academy of Clinical Biochemistry 13 recommend routine screening for hypothyroidism in women beginning in the fth decade of life. 4 The National Academy of Sciences (NAS) in the United States has been mandated by the US Congress to determine whether the Medicare programme should cover the cost of routine TSH screening and the Institute of Medicine of the NAS has selected a panel of experts to make recommendations by 2003. 14 Others have more recently advised a more aggressive approach to the detection of undiagnosed hypothyroidism and suggested that TSH testing is indicated in all individuals with goitre or other signs or symptoms of hypothyroidism. 4TSH screening is recommended for those individuals who have disorders with an increased risk for hypothyroidism, including in otherwise healthy women every ve years beginning at age 35 years, in men beginning at age 45 years 4 and in women who are contemplating pregnancy or are early in the rst trimester of pregnancy (to protect fetal brain development)15-18 and in postpartum women. 4,19Assays for TSH using DBS specimens are routinely used to screen newborn babies for primary hypothyroidism. 20 However, for several age-related reasons, these neonatal tests are not suitable for screening adult specimens. The ratio of red cells to ...

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Background and Objective: Hypothyroidism and autoimmune thyroiditis are more prevalent than previously considered in women during pregnancy and the postpartum, and are associated with adverse effects on the mother and her fetus. We determined the efficacy and accuracy of screening women for primary hypothyroidism and autoimmune thyroiditis by testing TSH and two thyroid antibodies (TAb): thyroperoxidase antibodies (TPOAb) and thyroglobulin antibodies (TgAb), in eluates of filter paper specimens collected during early pregnancy and the postpartum. Methods: We enrolled 494 first-trimester pregnant women with no exclusion criteria into a prospective study to detect primary hypothyroidism and autoimmune thyroiditis. Finger stick blood was applied to filter paper, dried in room air, eluted, and promptly tested for TSH and TAb. A total of 178 of the pregnant women (36%) were tested in the early postpartum. Women with abnormal results had confirmatory serum tests. Results: It was found that 91 pregnant women (18.4%) and 43 postpartum women (24.2%) had abnormal TSH values ( > 4.0 mU/L) and/or positive TAb; 140 pregnant women (28.3%) had TSH values > 2.5 mU/L. All subjects with TSH values > 4.0 mU/L tested positive for TAb. Eighteen women (3.6%) who tested normal during pregnancy tested abnormal in the postpartum. Conclusions: This study confirms that TSH and TPOAb measured in eluates of blood-spotted filter paper specimens are excellent screening tests to detect primary hypothyroidism and autoimmune thyroiditis in pregnant and postpartum women. Results are very comparable to serum data in this population published in the literature.