1. Baloch Z, Carayon P, Conte-Devolx B, et al. Laboratory medicine practice guidelines. Laboratory support for the diagnosis and monitoring of thyroid disease. Thyroid 2003;13:3.
2. Dayan CM. Interpretation of thyroid function tests. Lancet 2001;357:619.
3. Seth J, Kellett HA, Caldwell G, et al. A sensitive immunoradiometric assay for serum thyroid stimulating hormone: a replacement for the thyrotrophin releasing hormone test? BMJ 1984; 289:1334.
4. Caldwell G, Kellett HA, Gow SM, et al. A new strategy for thyroid function testing. Lancet 1985;i:1117.
5. Hall R. The need for more sensitive assays for the measurement of thyroid-stimulating hormone (TSH) and the long-acting thyroid stimulator (LATS). Clin Endocrinol (Oxf) 1974;3:361.
6. Spencer CA, Takeuchi M, Kazarosyan M. Current status and performance goals for serum thyrotropin (TSH) assays. Clin Chem 1996;42:140.
7. Nicoloff JT, Spencer CA. The use and misuse of the sensitive thyrotropin assays. J Clin Endocrinol Metab 1990;71:553.
8. Spencer CA, LoPresti JS, Patel A, et al. Applications of a new chemiluminometric thyrotropin assay to subnormal measurement. J Clin Endocrinol Metab 1990;70:453.
9. Spencer CA, Takeuchi M, Kazarosyan M, et al. Interlaboratory/intermethod differences in functional sensitivity of immunometric assays of thyrotropin (TSH) and impact on reliability of measurement of subnormal concentrations of TSH. Clin Chem 1995;41:367.
10. McConway MG, Chapman RS, Beastall GH, et al. How sensitive are immunometric assays for thyrotropin? Clin Chem 1989; 35:289.
11. Spencer CA, Schwarzbein D, Guttler RB, et al. Thyrotropin (TSH)-releasing hormone stimulation test responses employing third and fourth generation TSH assays. J Clin Endocrinol Metab 1993;76:494.
12. Ekins R. The free hormone hypothesis and measurement of free hormones. Clin Chem 1992;38:1289.
13. Ekins R. Measurement of free hormones in blood. Endocr Rev 1990;11:5.
14. Kaptein E. Nonthyroidal illness. In: Henneman G KE, ed. Thyroid international. Darmstadt: Merck KG, 1998.
15. Beckett GJ, Wilkinson E. Thyroid hormone metabolism in non-thyroidal illness. CPD Bulletin of Clinical Biochemistry 1998;1:9.
16. Christofides N. Free analyte immunoassay. In: Wild D, ed. The immunoassay handbook. 2nd ed. London: Nature Publishing Group, 2001:61.
17. Faber J, Waetjen I, Siersbaek-Nielsen K. Free thyroxine measured in undiluted serum by dialysis and ultrafiltration: effects of non-thyroidal illness, and an acute load of salicylate or heparin. Clin Chim Acta 1993;223:159.
18. Tikanoja S. Ultrafiltration devices tested for use in a free thyroxine assay validated by comparison with equilibrium dialysis. Scand J Clin Lab Invest 1990;50:663.
19. Stockigt J. Free thyroid hormone measurement. A critical appraisal. Endocrinol Metab Clin North Am 2001;30:265.
20. Nelson JC, Wilcox RB. Analytical performance of free and total thyroxine assays. Clin Chem 1996;42:146.
21. Holm SS, Andreasen L, Hansen SH, et al. Influence of adsorption and deproteination on potential free thyroxine reference methods. Clin Chem 2002;48:108.
22. Wang R, Nelson JC, Wilcox RB. Salsalate and salicylate binding to and their displacement of thyroxine from thyroxine-binding globulin, transthyrin, and albumin. Thyroid 1999;9: 359.
23. Hennemann G, Everts ME, de Jong M, et al. The significance of plasma membrane transport in the bioavailability of thyroid hormone. Clin Endocrinol (Oxf) 1998;48:1.
24. Lim CF, Stockigt JR, Curtis AJ, et al. A naturally occurring furan fatty acid enhances drug inhibition of thyroxine binding in serum. Metabolism 1993;42:1468.
25. Lim CF, Stockigt JR. Influence of uremic toxins and nonesterified fatty acids on drug and thyroid hormone binding in serum. Clin Chem 1998;44:2380.
26. Ekins R. Analytic measurements of free thyroxine. Clin Lab Med 1993;13:599.
27. Christofides ND, Wilkinson E, Stoddart M, et al. Serum thyroxine binding capacity-dependent bias in an automated free thyroxine assay. J Immunoassay 1999;20:201.
28. Christofides ND, Wilkinson E, Stoddart M, et al. Assessment of serum thyroxine binding capacity-dependent biases in free thyroxine assays. Clin Chem 1999;45:520.
29. Bayer MF. Free thyroxine results are affected by albumin concentration and nonthyroidal illness. Clin Chim Acta 1983;130:391.
30. Csako G, Zweig MH, Benson C, et al. On the albumin dependence of measurements of free thyroxin. I. Technical performance of seven methods. Clin Chem 1986;32:108.
31. Csako G, Zweig MH, Benson C, et al. On the albumin-dependence of measurements of free thyroxin. II. Patients with non-thyroidal illness. Clin Chem 1987;33:87.
32. Csako G, Zweig MH, Glickman J, et al. Direct and indirect techniques for free thyroxin compared in patients with nonthyroidal illness. I. Effect of free fatty acids. Clin Chem 1989;35: 102.
33. Wilkins TA. Albumin in analog FT4 assay reagents: the facts. Clin Chem 1987;33:1293.
34. Wilkins TA, Midgley JE. Albumin-dependence of free thyroxin in nonthyroidal illness. Clin Chem 1987;33:1494.
35. Ekins R. One-step, labeled-antibody assay for measuring free thyroxine. I. Assay development and validation. Clin Chem 1992;38:2355.
36. Sapin R. Serum thyroxine binding capacity-dependent bias in five free thyroxine immunoassays: assessment with serum dilution experiments and impact on diagnostic performance. Clin Biochem 2001;34:367.
37. Sapin R, d’Herbomez M. Free thyroxine measured by equilibrium dialysis and nine immunoassays in sera with various serum thyroxine-binding capacities. Clin Chem 2003;49: 1531.
38. Faber J, Siersbaek-Nielsen K. Serum free 3,5,3′-triiodothyronine (T3) in non-thyroidal somatic illness, as measured by ultrafiltration and immunoextraction. Clin Chim Acta 1996;256: 115.
39. Sapin R, Schlienger JL, Kaltenbach G, et al. Determination of free triiodothyronine by six different methods in patients with non-thyroidal illness and in patients treated with amiodarone. Ann Clin Biochem 1995;32:314.
40. Wiersinga WM. Thyroid hormone metabolism in non-thyroidal illness. Curr Opin Endocrinol Diabetes 1996;3:422.
41. Schussler GC. The thyroxine binding proteins. Thyroid 2000; 10:141.
42. Despres N, Grant AM. Antibody interference in thyroid assays: a potential for clinical misinformation. Clin Chem 1998;44: 440.
43. Surks MI, Sievert R. Drugs and thyroid function. N Engl J Med 1995;333:1688.
44. Kailajarvi M, Takala T, Gronroos P, et al. Reminders of drug effects on laboratory test results. Clin Chem 2000;46:1395.
45. Brabant A, Brabant G, Schuermeyer T, et al. The role of glucocorticoids in the regulation of thyrotropin. Acta Endocrinol (Copenh) 1989;121:95.
46. Kaptein EM, Spencer CA, Kamiel MB, et al. Prolonged dopamine administration and thyroid hormone economy in normal and critically ill subjects. J Clin Endocrinol Metab 1980;51:387.
47. Geffner DL, Hershman JM. Beta-adrenergic blockade for the treatment of hyperthyroidism. Am J Med 1992;93:61.
48. Hawkins RC. Furosemide interference in newer free thyroxine assays. Clin Chem 1998;44:2550.
49. Lim CF, Munro SL, Wynne KN, et al. Influence of nonesterified fatty acids and lysolecithins on thyroxine binding to thyroxine-binding globulin and transthyretin. Thyroid 1995;5:319.
50. Munro SL, Lim CF, Hall JG, et al. Drug competition for thyroxine binding to transthyretin (prealbumin): comparison with effects on thyroxine-binding globulin. J Clin Endocrinol Metab 1989;68:1141.
51. Surks MI, DeFesi CR. Normal serum free thyroid hormone concentrations in patients treated with phenytoin or carbamazepine. A paradox resolved. JAMA 1996;275:1495.
52. Beckett GJ, Ratcliffe WA, Chapman B, et al. Non-isotopic, two-step free thyroxine immunoassay: a better measure of free thyroxine than analogue radioimmunoassay. Ann Clin Biochem 1990;27:581.
53. Beckett GJ, Wilkinson E, Rae PW, et al. The clinical utility of a non-isotopic two-step assay (DELFIA) and an analogue radioimmunoassay (SimulTRAC) for free thyroxine compared. Ann Clin Biochem 1991;28:335.
54. Mendel CM, Frost PH, Kunitake ST, et al. Mechanism of the heparin-induced increase in the concentration of free thyroxine in plasma. J Clin Endocrinol Metab 1987;65:1259.
55. Hollowell JG, Staehling NW, Flanders WD, et al. Serum TSH, T4, and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III). J Clin Endocrinol Metab 2002;87: 489.
56. Brabant G, Prank K, Hoang-Vu C, et al. Hypothalamic regulation of pulsatile thyrotopin secretion. J Clin Endocrinol Metab 1991;72:145.
57. Elmlinger MW, Kuhnel W, Lambrecht HG, et al. Reference intervals from birth to adulthood for serum thyroxine (T4), triiodothyronine (T3), free T3, free T4, thyroxine binding globulin (TBG) and thyrotropin (TSH). Clin Chem Lab Med 2001; 39:973.
58. Gow SM, Kellett HA, Seth J, et al. Limitations of new thyroid function tests in pregnancy. Clin Chim Acta 1985;152:325.
59. Price A, Obel O, Cresswell J, et al. Comparison of thyroid function in pregnant and non-pregnant Asian and western Caucasian women. Clin Chim Acta 2001;308:91.
60. Andersen S, Pedersen KM, Bruun NH, et al. Narrow individual variations in serum T4 and T3 in normal subjects: a clue to the understanding of subclinical thyroid disease. J Clin Endocrinol Metab 2002;87:1068.
61. Browning MC, Ford RP, Callaghan SJ, et al. Intra- and interindividual biological variation of five analytes used in assessing thyroid function: implications for necessary standards of performance and the interpretation of results. Clin Chem 1986;32:962.
62. Boscato LM, Stuart MC. Heterophilic antibodies: a problem for all immunoassays. Clin Chem 1988;34:27.
63. John R, Henley R. Antibody interference in free thyroxine assays. Ann Clin Biochem 1992;29:472.
64. John R, Othman S, Parkes AB, et al. Interference in thyroid-function tests in postpartum thyroiditis. Clin Chem 1991;37: 1397.
65. Kricka LJ. Interferences in immunoassay—still a threat. Clin Chem 2000;46:1037.
66. Ismail AA, Walker PL, Cawood ML, et al. Interference in immunoassay is an underestimated problem. Ann Clin Biochem 2002;39:366.
67. Stockigt JR, DeGaris M, Barlow JW. “Unbound-analogue” methods for free T4: a note of caution. N Engl J Med 1982; 307:126.
68. Sunthornthepvarakul T, Likitmaskul S, Ngowngarmratana S, et al. Familial dysalbuminemic hypertriiodothyroninemia: a new, dominantly inherited albumin defect. J Clin Endocrinol Metab 1998;83:1448.
69. Curtis AJ, Scrimshaw BJ, Topliss DJ, et al. Thyroxine binding by human transthyretin variants: mutations at position 119, but not position 54, increase thyroxine binding affinity. J Clin Endocrinol Metab 1994;78:459.
70. Stockigt JR, Stevens V, White EL, et al. “Unbound analog” radioimmunoassays for free thyroxin measure the albumin-bound hormone fraction. Clin Chem 1983;29:1408.
71. Stockigt JR, Dyer SA, Mohr VS, et al. Specific methods to identify plasma binding abnormalities in euthyroid hyperthyroxinemia. J Clin Endocrinol Metab 1986;62:230.
72. Seth J, Beckett G. Diagnosis of hyperthyroidism: the newer biochemical tests. Clin Endocrinol Metab 1985;14:373.
73. Snyder PJ, Utiger RD. Inhibition of thyrotropin response to thyrotropin-releasing hormone by small quantities of thyroid hormones. J Clin Invest 1972;51:2077.
74. Forfar JC, Feek CM, Miller HC, et al. Atrial fibrillation and isolated suppression of the pituitary-thyroid axis: response to specific antithyroid therapy. Int J Cardiol 1981;1:43.
75. Sawin CT. Subclinical hyperthyroidism and atrial fibrillation. Thyroid 2002;12:501.
76. Faber J, Jensen IW, Petersen L, et al. Normalization of serum thyrotrophin by means of radioiodine treatment in subclinical hyperthyroidism: effect on bone loss in postmenopausal women. Clin Endocrinol (Oxf) 1998;48:285.
77. Toft AD. Subclinical hyperthyroidism. N Engl J Med 2001; 345:512.
78. Cohen JH, Ingbar SH, Braverman LE. Thyrotoxicosis due to ingestion of excess thyroid hormone. Endocr Rev 1989;10:113.
79. Page SR, Sheard CE, Herbert M, et al. A comparison of 20 or 40 mg per day of carbimazole in the initial treatment of hyperthyroidism. Clin Endocrinol (Oxf) 1996;45:511.
80. Toft AD, Irvine WJ, Hunter WM, et al. Anomalous plasma TSH levels in patients developing hypothyroidism in the early months after 131I therapy for thyrotoxicosis. J Clin Endocrinol Metab 1974;39:607.
81. Young ET, Steel NR, Taylor JJ, et al. Prediction of remission after antithyroid drug treatment in Graves’ disease. QJM 1988; 66:175.
82. Takamatsu J, Kuma K, Mozai T. Serum triiodothyronine to thyroxine ratio: a newly recognized predictor of the outcome of hyperthyroidism due to Graves’ disease. J Clin Endocrinol Metab 1986;62:980.
83. Panesar NS, Li CY, Rogers MS. Reference intervals for thyroid hormones in pregnant Chinese women. Ann Clin Biochem 2001;38:329.
84. Talbot JA, Lambert A, Anobile CJ, et al. The nature of human chorionic gonadotrophin glycoforms in gestational thyrotoxicosis. Clin Endocrinol (Oxf) 2001;55:33.
85. Hershman JM. Human chorionic gonadotropin and the thyroid: hyperemesis gravidarum and trophoblastic tumors. Thyroid 1999;9:653.
86. Pop VJ, Brouwers EP, Vader HL, et al. Maternal hypothyroxinaemia during early pregnancy and subsequent child development: a 3-year follow-up study. Clin Endocrinol (Oxf) 2003; 59:282.
87. Meier C, Trittibach P, Guglielmetti M, et al. Serum thyroid stimulating hormone in assessment of severity of tissue hypothyroidism in patients with overt primary thyroid failure: cross sectional survey. BMJ 2003;326:311.
88. Cooper DS. Subclinical hypothyroidism. N Engl J Med 2001; 345:260.
89. Cotton GE, Gorman CA, Mayberry WE. Suppression of thyrotropin (h-TSH) in serums of patients with myxedema of varying etiology treated with thyroid hormones. N Engl J Med 1971;285:529.
90. Sagud M, Pivac N, Muck-Seler D, et al. Effects of sertraline treatment on plasma cortisol, prolactin and thyroid hormones in female depressed patients. Neuropsychobiology 2002;45: 139.
91. Harel Z, Biro FM, Tedford WL. Effects of long term treatment with sertraline (Zoloft) simulating hypothyroidism in an adolescent. J Adolesc Health 1995;16:232.
92. Toft AD, Beckett GJ.Thyroid function tests and hypothyroidism. BMJ 2003;326:295.
93. Spencer C, Eigen A, Shen D, et al. Specificity of sensitive assays of thyrotropin (TSH) used to screen for thyroid disease in hospitalized patients. Clin Chem 1987;33:1391.
94. Hamblin PS, Dyer SA, Mohr VS, et al. Relationship between thyrotropin and thyroxine changes during recovery from severe hypothyroxinemia of critical illness. J Clin Endocrinol Metab 1986;62:717.
95. Wilcox RB, Nelson JC, Tomei RT. Heterogeneity in affinities of serum proteins for thyroxine among patients with non-thyroidal illness as indicated by the serum free thyroxine response to serum dilution. Eur J Endocrinol 1994;131:9.
96. Stockigt JR. Guidelines for diagnosis and monitoring of thyroid disease: nonthyroidal illness. Clin Chem 1996;42:188.
97. Ladenson PW, Singer PA, Ain KB, et al. American Thyroid Association guidelines for detection of thyroid dysfunction. Arch Intern Med 2000;160:1573.
98. Oliveira JH, Persani L, Beck-Peccoz P, et al. Investigating the paradox of hypothyroidism and increased serum thyrotropin (TSH) levels in Sheehan’s syndrome: characterization of TSH carbohydrate content and bioactivity. J Clin Endocrinol Metab 2001;86:1694.
99. Price A, Weetman AP. Screening for central hypothyroidism is unjustified. BMJ 2001;322:798.
100. Waise A, Belchetz PE. Lesson of the week: unsuspected central hypothyroidism. BMJ 2000;321:1275.
101. Wardle CA, Fraser WD, Squire CR. Pitfalls in the use of thyrotropin concentration as a first-line thyroid-function test. Lancet 2001;357:1013.
102. Lamberts SW, de Herder WW, van der Lely AJ. Pituitary insufficiency. Lancet 1998;352:127.
103. Mitchell DR, Parvin CA, Gronowski AM. Rules-based detection of discrepancies between TSH and free T4 results. Clin Chim Acta 2003;332:89.