This document discusses thyroid hormone tests (T3, T4, TSH, fT4) and their principles, procedures, and clinical significance. It describes the hormones T3 and T4, how they are regulated by the hypothalamus-pituitary-thyroid axis, and common thyroid disorders like hypothyroidism and hyperthyroidism. It provides details on specific assays for the hormones, including radioimmunoassay, immunoradiometric assay, enzyme immunoassay, and electrochemiluminescent assay. Reference ranges and clinical implications of test results are also covered.

1. TUTOR IMUNOLOGI PEMERIKSAAN HORMON TIROID (T3, T4, TSH, fT4) Lestari Ekowati,dr. SitiRochmatoenHarmadji, dr., SpPK(K) Selasa, 22 Maret 2011

3. hormon yang bekerjapada axis tersebut

4. pengaruhpada organ lainnya

5. pengaruhluarterhadap axis tersebutkelainanendokrin terseringkedua setelah diabetes mellitus berpengaruhkehampir seluruhtubuh

6. HORMON TIROID TUTOR IMUNOLOGI 3 Ada 2 : 1. Tiroksin (Thyroxine = T4 = L-3,5,3’,5’-tetraiodothyronin) 2. Triiodothyronine (T3 = L-3,5,3’-triiodothyronine) Kuantitatifterbanyak : T4 T3 sedikit, tapiaktifsecarabiologis (potensi 3 x T4) T4 sebagaiprecursor / prohormon Biladiperlukanakandipecahdi jaringanuntukmembentuk T3

7. Pengaruhfisiologishormontiroid TUTOR IMUNOLOGI 4

8. Pengaturanhormontiroid TUTOR IMUNOLOGI 5

9. Mekanismeumpanbalik TUTOR IMUNOLOGI 6

10. KELAINAN TIROID TUTOR IMUNOLOGI KELAINAN TIROID HIPOTIROID GOITER HIPERTIROID EUTIROID OBAT DIFUS NODULAR UNI NODULAR MULTI NODULAR 7 KLINIS SUB KLINIS KLINIS SUB KLINIS

11. TUTOR IMUNOLOGI Th 70-an Th 80-an 8 Radioimmunoassay (RIA) Immunoradiometric assay (IRMA) Enzyme immunoassay (EIA) Enzyme-linked immunoassay (ELISA) PEMERIKSAAN HORMON TIROID Electrochemiluminescent assay (ECLIA)

13. MenggunakanRadioaktifsebagai label, seperti : 131I, 125I, 3H

14. Prinsipkompetitif : analit yang dideteksiberkompetisidengananalit yang berlabelradioaktifuntukberikatandenganantibodiAntibodipada fasepadat Ag berlabelradioaktif Ag takberlabel (sampel) Ikatan Ag-Abspesifik

15. IMMUNORADIOMETRIC ASSAY (IRMA) TUTOR IMUNOLOGI 10 Prinsip : ikatan non-kovalenreversibelantara antigen danantibodispesifik yang dilabeldenganradioaktif Antibodipadafasepadat Antibodiberlabelradioaktif Ikatan Ag-Abspesifik Sampel

17. glucose-6-phosphate-dehydrogenase

18. alkaline phosphatase

19. ß-D-galactosidaseEIA pertama kali menggunakanprinsipkompetitifsepertipada RIA

20. ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) TUTOR IMUNOLOGI 12 Bagiandari EIA Non kompetitif EIA Lebihsensitif (<1 pg/mL) Indirek: reagenberlabelenzym tidakikutbereaksipadaikatan Ag-Abawal Sandwich = capture : jikaAb yang dilekatkanpadafasepadat

22. Molekul yang seringdigunakansebagaichemiluminescense : luminol, acridium esters, ruthenium derivativesdannitrophenyl oxalate.

23. Paling sensitifdibanding RIA dan EIA.

24. Reagenstabildan non toksik.TUTOR IMUNOLOGI

25. Pengambilansampel TUTOR IMUNOLOGI Tidakperlu persiapankhusus Bahan : serum, plasma EDTA atau heparin Tidakperlumerubah polamakan & aktifitasfisik Disimpan 2-8oC, 3-5 hari Beku : stabilsampai ± 30 hari Obatberhentisampaites selesaidikerjakan Tidakhemolisisataulipemik Adajugaobat-obatan yang tetapdimintauntukdiminumkarenaingindiketahuipengaruhnya 9 14

26. PEMERIKSAAN HORMON TIROID DI LAB. PK RSUD DR SOETOMO SURABAYA TUTOR IMUNOLOGI T3, T4, TSH, fT4 Senin, Rabu, Jum’at EIA, Thyrolisa, (Indec-Diagnostic) 15

27. PEMERIKSAAN T3 TUTOR IMUNOLOGI Varian tirotoksik : kadar T3 ↑, T4 normal (T3 tirotoksikosis) Peningkatan T3 tanpapeningkatan T4 : gejalaawaltirotoksikosisrekurenpada pasien yang mendapatterapi 16 T4 dan T3 sebagianbesar terikatpada Thyroxine Binding Globuline (TBG) Konsentrasi T3 <<< T4 Potensimetabolik T3 >>>

28. Prinsippemeriksaan T3 TUTOR IMUNOLOGI 1 17 EIA Kompetitif Goat anti-mouse IgG T3 conjugate Mouse Ab anti-T3 Sampel

29. Prosedurpemeriksaan T3 TUTOR IMUNOLOGI 18 50 µL Standar/ Sampel/ Kontrol Campur rata 30 ‘’ Campur Rata 30 ‘’ Microwells 100 µL Working conjugate reagen 50 µL ReagenAntibodi Inkubasi Suhukamar 60’ Campur rata 30 ‘’ Inkubasi Suhukamar 20’ Buang Cuci-bilas 5 x Hilangkansisa air dg absorbent paper Baca OD pada 450 nm dalam 15’ 100 µL Substrate solution 100 µL Stop solution

30. Penghitunganhasil TUTOR IMUNOLOGI 19 Absorbans Dihitung rata-rata absorbansuntuktiap set standar, kontrol, sampel Konsentrasi (ng/mL) Konsentrasi T3 ditentukandenganmemasukkannilaiabsorbanstiapsampelkedalamkurvastandar.

31. TUTOR IMUNOLOGI 20 Range normal : 0,6-1,85 ng/mL. Kadar T3 total dalam serum parareldengan TBG Peningkatankadar T3 dapatterjadipada penderitahipotiroid yang sedangmendapatkanterapi Konsentrasi minimal yang dapatterdeteksi : 0,2 ng/mL.

32. Keterbatasanprosedur 21 Hasil yang benar&akuratdiperolehjikaprosedurpemeriksaandilakukansesuaiinstruksi Prosedurpencuciansangatpenting. Pencucian yang tidakbenarakanmenghasilkanpresisi yang burukdanpembacaanabsorbans yang tinggipalsu. Sampel serum yang lipemik, hemolisisataukeruhtidakdapatdiperiksa. Hasil yang diperolehharusdigunakanbersamadenganprosedur diagnosis daninformasilainnya TUTOR IMUNOLOGI

34. Thyroxine binding pre albumin (TBPA) 20%

35. Albumin 10%0,03% dalamkeadaantidakterikat. ProteolisisThyroglobulinakan melepaskan T4 kedalamalirandarah 22 T4 total : skrininggangguantiroid T4 ↑ : hipertiroidisme T4 ↓ : hipotiroidisme Text T4 Text

36. Prinsippemeriksaan T4 TUTOR IMUNOLOGI 23 EIA Kompetitif Antibodi Anti T4 T4 conjugate Sampel

37. Prosedurpemeriksaan T4 TUTOR IMUNOLOGI 24 25 µL Standar/ Sampel/ Kontrol Campur Rata 30 ‘’ Inkubasi Suhukamar 60’ Microwells 100 µL Working conjugate reagen Campur rata 30 ‘’ Buang Cuci-bilas 5 x 100 µL Substrate solution Hilangkansisa air dg absorbent paper Inkubasi Suhukamar 20’ 100 µL Stop solution Baca OD 450 nm, 15’

38. 25 Kadar T4 normal : 5,0 -13,0 ng/mL Sebaiknyasetiaplaboratoriummenentukankadarnyasendiridisesuaikandengangeografisdanpopulasi yang ada Konsentrasi minimal yang dapatterdeteksiadalah 0,4 ng/mL. TUTOR IMUNOLOGI

39. PEMERIKSAAN TSH TUTOR IMUNOLOGI B A C D E 26 disekresiolehlobus anterior kelenjarhipofisis(pituitary) mempengaruhiproduksidanpelepasan T3 dan T4 darikelenjartiroid sensitifuntukmendiagnosishipotiroidisme primer atausekunder TSH glikoprotein, BM ± 28.000 dalton terdiridari 2 subunit : alphadanbeta.

40. TUTOR IMUNOLOGI 27 TSH, LH, FSH, danhCG, memilikirantaialpha yang identik. Rantaibetaberbedanamunmengandungregiodenganurutanasam amino yang identik. Regio yang homolog inidapatmenyebabkanreaksisilang(cross reaction) denganbeberapaantisera TSH poliklonal. Kadar TSH sangatrendah, namunsangatpentinguntukmengaturfungsitiroid yang normal. Pelepasan TSH diaturolehTSH-releasing hormone (TRH) yang diproduksiolehhipotalamus. Kadar TSH dan TRH berbandingterbalikdengankadarhormontiroid.

41. Prinsippemeriksaan TSH TUTOR IMUNOLOGI 28 ELISA SANDWICH Antibodi Anti-TSH (murine) Antibodi Anti TSH (goat) Sampel

42. Prosedurpemeriksaan TSH TUTOR IMUNOLOGI 29 100 µL Working conjugate reagen Campur rata 30 ‘’ Inkubasi Suhukamar 60’ 100 µL Standar/ Sampel/ Kontrol Microwells Inkubasi Suhukamar 20’ Campur rata 30 ‘’ Buang Cuci-bilas 5 x 100 µL TMB Substrate solution Hilangkansisa air dg absorbent paper 100 µL Stop solution Baca OD 450 nm, 15’

43. TUTOR IMUNOLOGI 30 Kadar TSH normal : 0,4 -6,0 µIU/mL Kadar TSH >10 µIU/mL : hipotiroidisme primer Kadar TSH rendah/tidakterdeteksi/normal : indikatorhipotiroidismesekunder (kegagalansekresi TSH atau TRH) Kadar rendah : hipersekresi T3 dan T4 padaGrave’s diseaseatautiroiditis DD : memeriksakadar TSH dan fT4 dalam serum secarasimultan Konsentrasimin.yangterdeteksi : 0,2 µIU/mL.

44. PEMERIKSAAN FREE T4 TUTOR IMUNOLOGI 31 T4 berikatandengan protein serum Hanya 0,03% T4 yang bebas, disebutsebagaiFree T4 (fT4), merupakanmetabolikaktif Hipertiroidisme primer -> produksi T4 >> -> kadar fT4 >> Hipotiroidisme primer -> produksi T4 < -> kadar fT4 < Kadar T4 total tergantungkadar TBG Kadar TBG dipengaruhioleh : obat, hormon steroid, kehamilan, danpenyakit non tiroid. Pemeriksaan fT4 : untukmengetahuikeseimbangan antara T4 bebasdan T4 yang terikat TBG Metodeinidapatmenggambarkan status tiroidsecaraumumdengansatumacampemeriksaan.

45. Prinsippemeriksaan fT4 TUTOR IMUNOLOGI 32 EIA Kompetitif AntibodiAnti-fT4 fT4 conjugate Sampel

46. Prosedurpemeriksaan fT4 TUTOR IMUNOLOGI 33 50 µL Standar/ Sampel/ Kontrol Inkubasi Suhukamar 60’ Campur rata 20-30 ‘’ Microwells 100 µL Thyroxineenzime conjugate Campur rata 30 ‘’ 100 µL Working Substrate solution Reagen A&B 1:1 Buang Cuci-bilas 5 x Hilangkansisa air dg absorbent paper 50 µL Stop solution Inkubasi Suhukamar 20’ Baca OD 450 nm, 30’

47. TUTOR IMUNOLOGI 1 2 3 4 fT4 dapatmemberikanpenilaian yang lebihakuratuntukpenilaian status tiroiddaripada T4 total Perubahan serum binding protein -> perubahan T4 total, namunkadar fT4 tetaptidakberubah fT4 ↑ : hipertiroidisme fT4 ↓ : hipotiroidisme. Range fT4 normal : 0,8 - 2,0 ng/dL 34

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49. NORMAL VALUE TUTOR IMUNOLOGI

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51. Kurvastandar TSH TUTOR IMUNOLOGI absorbans Konsentrasi TSH µIU/mL

52. Obat yang mempengaruhitiroid Dopamine : mengurangisekresi TSH Glukokortikoid : mengurangisekresi TSH Lithium : menurunkan fT4 Yodida : menurunkan fT4 Amiodaron : meningkatkanataumenekan fT4 Estrogen : mempengaruhi TBG Androgen : mempengaruhi TBG TUTOR IMUNOLOGI

53. Pemantauanterapi TUTOR IMUNOLOGI Perubahan TSH serum lambat, butuhwaktubeberapabulanuntukkembalikerentang normal Pengukuran T4 serum lebihbaikdaripada TSH sebagaiujitunggalfungsitiroidbilakondisi steady state belumtercapai, misalnyapadafaseawalpengobatantirotoksikosis

54. interferensi Reaksisilang Antibodianalit endogen Antibodiheterofilik Interaksiobat Heparin merangsang lipoprotein lipase melepaskanasamlemakbebas yang menghambatikatan T4 pada protein serum Furosemide Uremia TUTOR IMUNOLOGI

55. TSH Anaklahir 4 hari 1.0-39.0 mIU/L 2-20 minggu 1.7-9.1 21 minggu-20th 0.7-64.0 Dewasa 21-54th 0.4-4.2 55-87 tahun 0.5-8.9 Kehamilan trimester 1 0.3-5.2 TUTOR IMUNOLOGI

56. T4 Neonatus > 6.5 ug/dL Dewasa 4.6-11.0 T3 Dewasa 20-50 tahun 70-204 ng/dL 50-90 tahun 40-181 T3 Dewasa 10-28 ng/dL FT4 Dewasa 0.8-2.0 ng/dL TUTOR IMUNOLOGI

58. synthesized via the iodination and covalent bonding of the phenyl portions of tyrosine residues found in an initial peptide, thyroglobulin, which is secreted into thyroid granules.

60. Efek T4 controlling the rate of metabolic processes in the body and influencing physical development, increase the concentration of nerve growth factor in the brains. Thyroxine is a prohormone and a reservoir for the active thyroid hormone triiodothyronine (T3), which is about four times more potent. T4 is converted in the tissues by deiodinases, including thyroid hormone iodine peroxidase (TPO), to T3. The "D" isomer is called "Dextrothyroxine" and is used as a lipid modifying agent. TUTOR IMUNOLOGI

61. Thyroxine can be measured as free thyroxine, which is an indicator of thyroxine activity in the body. It can also be measured as total thyroxine, which also depends on the thyroxine that is bound to thyroxine-binding globulin. A related parameter is the free thyroxine index, which is total thyroxine multiplied by thyroid hormone uptake, which, in turn, is a measure of the unbound thyroxine binding globulins. The normal human adult range of T4 in blood is 4 - 11 mcg/dL TUTOR IMUNOLOGI

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65. Triiodothyronine effects of T3 on target tissues are roughly four times more potent than those of T4. Of the thyroid hormone that is produced, just about 20% is T3, whereas 80% is produced as T4. Roughly 85% of the circulating T3 is later formed in the thyroid by removal of the iodine atom from the carbon atom number five of the outer ring of T4. In any case, the concentration of T3 in the human blood plasma is about one-fortieth of that of T4. This is observed in fact because of the short half-life of T3, which is only 2.5 days. This compares with the half-life of T4, which is about 6.5 days. TUTOR IMUNOLOGI

66. T3 and T4 are carried in the blood - bound to plasma proteins There are three main proteins that the two hormones are bound to Thyronine-binding globulin (TBG) is a glycoprotein that has a higher affinity for T4 than for T3 Transthyretin is also a glycoprotein, but with a higher affinity for T3 than for T4. Albumin, low affinity, but, due to the large availability of albumin, it has a high capacity. TUTOR IMUNOLOGI

67. Thyroidal Radioiodine Uptake This test does not reflect the patient's thyroid status, but determines the turnover of iodine in the gland. It measures 6 or 24 hours uptake of 131I or 123I after the oral administration of the iodine. Its main use is in the differential diagnosis of the etiology of hyperthyroidism (Table 7). It should be used only when the cause of hyperthyroidism is in doubt, such as in patients with hyperthyroid symptoms, small goiters and no evidence of exophthalmopathy. It is also indicated in the hyperthyroid phase in postpartum thyroiditis to differentiate Graves' disease from destructive thyroiditis. TUTOR IMUNOLOGI

68. Company name www.themegallery.com TBG and the thyroxine binding site. (a) Structure of TBG with thyroxine (space-filled). The upper half of the Aβ-sheet (blue) is opened, with initial insertion of the reactive loop (red) to P14 threonine, 14 residues before the reactive center P1. (b) Binding pocket showing thyroxine in stick form enclosed between strands 3–5 of the B-sheet and helices H and A and with iodine atoms, contoured at 5 times rms density in a log-likelihood gradient map for anomalous scattering

69. Company name www.themegallery.com Binding and triggered release of thyroxine. (a) Interactions with adjacent side chains anchor thyroxine within the pocket. Thyroxine release will be triggered on full insertion of P14 threonine (space-filled upper left) displacing Tyr-241 and disrupting the H-bonds that anchor thyroxine and the flanking peptide loop between s4B and s5B (blue). This network will be similarly disrupted by the common presence (19) in Australian aborigines of a Thr at 191 (circled red; see also Fig. 4). (b) The triggered movement of the flanking s4B–5B loop is shown in the homologous pocket in antichymotrypsin. The open pocket of TBG before loop insertion (blue) matches that of active antichymotrypsin (gray). Transition to the fully inserted loop (cyan) or to the partially inserted δ-form (green) in antichymotrypsin both result in a 4- to 5-Å shift of the loop with a contraction of the binding pocket.

70. TMB TMB (3,3′,5,5′-tetramethylbenzidine) is a chromogen that yields a blue color when oxidized, typically as a result of oxygen radicals produced by the hydrolysis of hydrogen peroxide by HRP. For kinetic or non-stopped ELISA assays, the TMB chromogen has maximal absorbances at 370nm and 652nm. The color then changes to yellow with the addition of sulfuric or phosphoric acid with maximum absorbance at 450nm. A green reaction product may result from partial conversion to the yellow product from the blue intermediate. TMB is very sensitive ELISA substrate and is more quickly oxidized than other HRP substrates, resulting in faster color development.

71. Free thyroxine index the amount of unbound, physiologically active thyroxine (T4) in serum. This amount is determined by direct assay or, more frequently, calculated on the basis of an in vitro uptake test. In this test the uptake (by resin or charcoal) of labeled triiodothyronine (T3) is measured; because T3 is less strongly bound by serum, it is used instead of T4. The free T4 index is then obtained by multiplying the T3 uptake by the total concentration of T4 in serum. www.themegallery.com Company name

72. FT4I, T7 assay, T12 assay Endocrinology A lab value for T3 uptake combined with total T4; FTI is a clinical parameter measured by RIA, used to evaluate thyroid function, calculated by T4 x %T3RU–resin uptake; the FTI is ↑ in hyperthyroidism and factitious hyperthyroidism and ↓ in hypothyroidism; it is falsely ↑ in heparin therapy and falsely ↓ in phenytoin and valproic acid therapy, and in the euthyroid sick syndrome TUTOR IMUNOLOGI

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