Standardization of Thyroid Function Tests

Transcription

1 Standardization of Thyroid Function Tests Saturday, Dec 3 rd th meeting Location: Nycomed Belgium 18 Brussels Linda Thienpont Linda.thienpont@ugent.be

2 Thyroid dysfunction: clinical importance Relatively high prevalence in adults Significant clinical consequences New perspectives resulting from research e.g.,1-3 Subclinical thyroid dysfunction linked to various adverse clinical outcomes (all-cause mortality; pregnancy) 1 Singh S et al. Impact of subclinical thyroid disorders on coronary heart disease, cardiovascular and all-cause mortality: a meta-analysis. Int J Cardiol 28;125: Haentjens P et al. Subclinical thyroid dysfunction and mortality: an estimate of relative and absolute excess all-cause mortality based on time-to-event data from cohort studies. Eur J Endocrinol 28;159: Negro R et al. Thyroid antibody positivity in the first trimester of pregnancy is associated with negative pregnancy outcomes. J Clin Endocrinol Metab 211;96:E92-4. Belgian Thyroid Club -39th meeting - Dec 3rd 211 2

3 Accuracy of clinical diagnosis limited Clinical manifestations of thyroid disease vary in character and severity among patients Symptoms often non-specific and slowly progressing Adequate laboratory assessment is needed Strategies for laboratory testing and interpretation are welcome Note: yearly volume of requests for testing of TSH and free thyroxine (FT4) alone is estimated to be in the order of 18 and 6 million US$, respectively# #Weinzierl C, Beckman-Coulter, personal communication (29). Belgian Thyroid Club -39th meeting - Dec 3rd 211 3

4 Lab testing and interpretation strategies Guidelines Ladenson PW et al. American Thyroid Association guidelines for detection of thyroid dysfunction. Arch Intern Med 2;16: Gharib H et al. Subclinical thyroid dysfunction: a joint statement on management from the American Association of Clinical Endocrinologists, the American Thyroid Association, and the Endocrine Society. J Clin Endocrinol Metab 25;9: Bahn RS et al. Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Thyroid 211;21: Belgian Thyroid Club -39th meeting - Dec 3rd 211 4

5 Lab testing and interpretation strategies Guidelines (continued) Demers LM et al. 22 Laboratory Medicine Practice Guidelines: laboratory support for the diagnosis and monitoring of thyroid disease. National Academy of Clinical Biochemistry (NACB) Washington (DC). oiddisease/pages/default.aspx. Abalovich M et al. Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 27;92:S1-S47. Stagnaro-Green A et al. Guidelines of the American Thyroid Association for the diagnosis and management of thyroid disease during pregnancy and postpartum. Thyroid 211;21:1-45. Belgian Thyroid Club -39th meeting - Dec 3rd 211 5

6 Lab testing and interpretation strategies Leading journals Dayan CM. Interpretation of thyroid function tests Lancet 21;357(9256): [Review]. Stockigt J. Assessment of thyroid function: towards an integrated laboratory-clinical approach. Clin Biochem Rev 23;24: Surks MI et al. Subclinical thyroid disease: scientific review and guidelines for diagnosis and management. JAMA 24;291: [Review]. Belgian Thyroid Club -39th meeting - Dec 3rd 211 6

7 Lab testing and interpretation strategies Not to forget: Hot topics currently under debate in scientific literature Among others: is screening for thyroid dysfunction in pregnancy worthwhile? e.g., 1,2 Do we need age-, gender- & ethnicity-specific TSH reference limits? e.g., 3 Should the TSH upper reference limit be lowered? e.g., 4,5 1 Lazarus JH 211 Screening for thyroid dysfunction in pregnancy: is it worthwhile? J Thyroid Res 211, Article ID doi:1.461/211/ Negro R et al. Thyroid antibody positivity in the first trimester of pregnancy is associated with negative pregnancy outcomes. J Clin Endocrinol Metab 211;96:E Boucai L et al. An approach for development of age-, gender-, and ethnicity-specific thyrotropin reference limits. Thyroid 211;21: Brabant Get al. Is there a need to redefine the upper normal limit of TSH? Eur J Endocrinol 26;154(5): Review. 5 Laurberg P et al. The TSH upper reference limit: where are we at? Nat Rev Endocrinol 211;7: Belgian Thyroid Club -39th meeting - Dec 3rd 211 7

8 A closer look into the strategies Guidelines sometimes quote absolute decision limits/cut-off values or reference intervals Literature sometimes reports on clinical trials in terms of absolute values without reference to the laboratory test used Examples: the panel defined the reference range of normal TSH concentration as miu/l the panel recommends thyroid hormone therapy in individuals with elevated serum TSH concentrations whose FT4 concentration is below the reference range of pmol/l a TSH of 2.5 miu/l has been accepted as the upper limit of normal TSH in the first trimester of pregnancy Belgian Thyroid Club -39th meeting - Dec 3rd 211 8

9 Measurement paradigm Prerequisite to work with absolute values Laboratory tests that claim the same measurand should give equivalent results within meaningful clinical constraints Belgian Thyroid Club -39th meeting - Dec 3rd 211 9

10 Measurement paradigm Do current thyroid function tests give equivalent results? Belgian Thyroid Club -39th meeting - Dec 3rd 211 1

11 Working Group for Standardization of Thyroid Function Tests (WG-STFT) Chair: LM Thienpont (since 25) Mission statement: Develop reference measurement systems for thyroid hormones, i.e., FT4 & FT3, TSH, TT4 & TT3 Standardize the tests Belgian Thyroid Club -39th meeting - Dec 3rd

12 Reference measurement system Material Calibration Procedure Value assignment Definition of measurand&unit Primary reference measurement procedure Traceability Primary calibrator Manufacturer s working calibrator Manufacturer s product calibrator Secondary reference measurement procedure Manufacturer s master procedure End user s routine measurement procedure Uncertainty Routine sample Result Belgian Thyroid Club -39th meeting - Dec 3rd

13 WG-STFT Mission statement Develop Reference materials Reference measurement procedures Reference laboratories Reference measurement system Before the mission statement standardize Assess the current standardization status and quality of performance Method comparison with a panel of native sera Investigate the feasibility of standardization Implement (sustainable) standardization Belgian Thyroid Club -39th meeting - Dec 3rd

14 WG-STFT Mission statement RMS for free thyroid hormones: accomplished References Thienpont et al. Measurement of free thyroxine in laboratory medicine Proposal of measurand definition. IFCC Working Group for Standardization of Thyroid Function Tests (WG-STFT). Clin Chem Lab Med 27;45: Thienpont et al. Proposal of a candidate international conventional reference measurement procedure for free thyroxine in serum. IFCC Working Group for Standardization of Thyroid Function Tests (WG-STFT). Clin Chem Lab Med 27;45: Van Houcke SK, Van Uytfanghe K, Shimizu E, Tani W, Umemoto M, Thienpont LM. IFCC Working Group for Standardization of Thyroid Function Tests (WG-STFT). IFCC international conventional reference procedure for the measurement of free thyroxine in serum. Clin Chem Lab Med 211;49: Belgian Thyroid Club -39th meeting - Dec 3rd

15 WG-STFT Mission statement RMS for total thyroid hormones: accomplished References Toussaint B, Klein CL, Wiergowski M. The certification of the mass fraction of thyroxine in a CRM intended for calibration. EUR EN (26). ISBN Ibidem. The certification of the mass fraction of triiodothyronine in a CRM intended for calibration. EUR EN (26). ISBN Thienpont LM, Van Uytfanghe K, Marriot J, Stokes P, Siekmann L, Kessler A, Bunk D, Tai S. Metrologic traceability of total thyroxine measurements in human serum: efforts to establish a network of reference measurement laboratories. Clin Chem 25;51: Thienpont LM, Van Uytfanghe K, Marriott J, Stokes P, Siekmann L, Kessler A, Bunk D, Tai S. Feasibility study of the use of frozen human sera in split-sample comparison of immunoassays with candidate reference measurement procedures for total thyroxine and total triiodothyronine measurements. Clin Chem 25;51: Belgian Thyroid Club -39th meeting - Dec 3rd

16 WG-STFT Mission statement RMS for TSH: accomplished References Stöckl D, Thienpont LM et al. Current Stage of Standardization of Measurements of Specific Polypeptides and Proteins Discussed in Light of Steps Needed Towards a Comprehensive Measurement System. Discussion paper from the Members of the EQA Working Group B on Target Values in External Quality Assessment. Eur J Clin Chem Clin Biochem 1997;35: Thienpont LM. Accuracy in Clinical Chemistry - Who Will Kiss Sleeping Beauty Awake? Clin Chem Lab Med 28;46: Thienpont LM, Van Houcke SK. Traceability to a common standard for protein measurements by immunoassay for in-vitro diagnostic purposes. Clin Chim Acta 21;411: Miller WG Thienpont LM et al. Roadmap for Harmonization of clinical laboratory measurement procedures. Clin Chem 211;57: Belgian Thyroid Club -39th meeting - Dec 3rd

17 WG-STFT Mission statement Assessment of the current standardization status and quality of performance: accomplished References Thienpont LM et al.; for the IFCC Working Group on Standardization of Thyroid Function Tests. Report of the IFCC Working Group for Standardization of Thyroid Function Tests. Part 1: Thyroid-Stimulating Hormone. Clin Chem 21; 56: Part 2: Free Thyroxine and Free Triiodothyronine. Clin Chem 21;56: Part 3: Total Thyroxine and Total Triiodothyronine. Clin Chem 21;56: Thienpont LM et al. Standardization activities in the field of thyroid function tests: a status report. Clin Chem Lab Med 21;48: Belgian Thyroid Club -39th meeting - Dec 3rd

18 Measurement paradigm Do current thyroid function tests give equivalent results? Belgian Thyroid Club -39th meeting - Dec 3rd

19 Standardization status Free thyroxine (FT4) IFCC WG-STFT Project phase I (28) Means, all (pmol/l). FT4, means (pmol/l) y =.9111x (E) y =.566x (D) FT4 ID-LC/MS (pmol/l) Difference, means, all (%) Mean MS A B C D E F G H I J K L M N P Q R Procedure F #3: +11% FT4 ID-LC/MS (pmol/l) 15 tests Means varied from 1 to 17 pmol/l Except 2 tests, all measured FT4 much lower than the RMP (up to 42%) Hyperthyroid FT4 conc. with 1 test, still eu- with another Standardization is needed Belgian Thyroid Club -39th meeting - Dec 3rd

20 Standardization status Free triiodothyronine (FT3) IFCC WG-STFT Project phase I (28) FT3 Means Routine (pmol/l) FT3 Routine (pmol/l) Mean MS 3.7 A B C D E F G H I J K M N O y = 1.14x +.4 (O) y =.7x +.1 (A) FT3 Difference Routine (%) FT3 ED ID-MS (pmol/l) FT3 ED ID-MS (pmol/l) 14 tests Means varied from 3.7 to 6.5 pmol/l Most tests were negatively biased vs the RMP (up to 3%) 1 test had a positive bias of 22% Standardization is needed Belgian Thyroid Club -39th meeting - Dec 3rd 211 2

21 Standardization status TSH IFCC WG-STFT Project phase I (28) TSH, medians (miu/l).. Means, all (miu/l) A B C E F G H I J K L M N O P R y = x -.72 (C) y =.845x (K) TSH All median (miu/l) Procedure Difference, means, all (%) R #39: +159% TSH All median log(miu/l) 16 tests Medians of 11 tests differed <1% from the surrogate RMP (overall median) Using the respective regression equations and a TSH RI from.4 to 4 miu/l, the most discrepant tests would give values ranging from.34 to 3.24 miu/l, and.39 to 4.55 miu/l Lowering the upper reference limit is impossible without standardization Belgian Thyroid Club -39th meeting - Dec 3rd

22 Standardization status Total thyroxine (TT4) IFCC WG-STFT Project phase I (28) TT4, means (nmol/l).. Means, all (nmol/l) A B C E F G H K L M P y = 1.251x (H) y =.785x (M: w ithout high) TT4 ID-LC/MS (nmol/l) Procedure Difference, means, all (%) TT4 ID-LC/MS (nmol/l) 11 tests Means varied from 75 to 12 nmol/l Overall good agreement with the RMP: 7 tests gave means that differed less than 1% Only 4 tests need standardization Belgian Thyroid Club -39th meeting - Dec 3rd

23 Standardization status Total triiodothyronine (TT3) IFCC WG-STFT Project phase I (28) TT3 Means Routine (nmol/l) TT3 Routine (nmol/l) Mean MS 1.2 A B C E F H I J K L N M 3. y = 1.31x +.1 (K) y = 1.17x -.23 (C) TT3 Difference Routine (%) TT3 ID-MS (nmol/l) TT3 ID-MS (nmol/l) 12 tests Means varied from 1.45 to 1.89 pmol/l Nearly all tests were positively biased vs the RMP: 7 deviated >1%; 2 of them even >2% (up to 32%) Standardization is needed Belgian Thyroid Club -39th meeting - Dec 3rd

24 Quality of performance Assessment of quality of performance Against quality specifications, e.g., TE limits. After recalculation of results with regression equation, e.g., FT4 best and worst quality of performance IFCC WG-STFT Project phase I (28) E-Diff Recal-R1/R1 (pmol/l) #8:.4 G-Diff Recal-R1/R1 (pmol/l) #8: FT4 ID-LC/MS (pmol/l) FT4 ID-LC/MS (pmol/l) Belgian Thyroid Club -39th meeting - Dec 3rd

25 Quality of performance Assessment of quality of performance IFCC WG-STFT Project phase I (28) TSH K 3 B 3 R 3 r 2 =.998 r 2 =.992 r 2 = TSH Diff Recal R eplicate (miu/l) TSH Mean All (miu/l) TSH Diff Recal R eplicate (miu/l) TS H Mean All (miu/l) TSH Diff Recal R eplicate (miu/l) TSH Mean All (miu/l) Belgian Thyroid Club -39th meeting - Dec 3rd

26 Free T4 in pregnancy Comparison (trimester specific) of FT4 values by ED ID-LC/tandem MS and 3 immunoassays in nonpregnant controls (n = 26) and pregnant (n = 17) 25 FT4 ED-ID/tandem MS 25 FT4 Cobas 2 2 Concentration (pmol/l) Δ9% Δ29% 5 Δ9% Δ25% Concentration (pmol/l) ~ ~ 15 Control 1st 2nd 3rd Control 1st 2nd 3rd 2 FT4 ARCHITECT 2 FT4 Immulite Concentration (pmol/l) ~ ~ Δ14% Concentration (pmol/l) Δ1% Δ25% ~ Control 1st 2nd 3rd Control 1st 2nd 3rd Belgian Thyroid Club -39th meeting - Dec 3rd

27 Free T4 in pregnancy Concentration (pmol/l) Anckaert E, Poppe K, Thienpont LM et al. FT4 immunoassays may display a pattern during pregnancy similar to the equilibrium dialysis ID LC/tandem MS candidate reference measurement procedure in spite of susceptibility towards binding protein alterations. Clin Chim Acta 21;411: FT4 ED-ID/tandem MS 1 Δ9% Δ29% 5 Δ9% Δ25% Concentration (pmol/l) FT4 Cobas ~ ~ Control 1st 2nd 3rd Control 1st 2nd 3rd 2 FT4 ARCHITECT 2 FT4 Immulite Concentration (pmol/l) ~ ~ Δ14% Concentration (pmol/l) Δ1% Δ25% ~ Control 1st 2nd 3rd Control 1st 2nd 3rd Belgian Thyroid Club -39th meeting - Dec 3rd

28 First conclusion Current thyroid function tests need standardization Diagnosis/follow-up against test specific reference intervals/clinical decision thresholds is still recommended Standardization efforts must be accompanied by assessment of the quality of thyroid tests Communicate in a transparent way with clinicians on the influence of analytical quality on a test result Infer adequate quality specifications preferably in consultation with clinicians Improve the quality of some thyroid function tests Belgian Thyroid Club -39th meeting - Dec 3rd

29 First conclusion Testing of FT4 in pregnancy Immunoassays are sensitive to binding protein alterations, but to a grossly different extent Some show the true changes of FT4 during pregnancy (as observed with the reference measurement procedure ED ID-LC/tandem MS) FT4 in pregnancy can be tested with commercial tests, but results have to be interpreted test specific; the same test should be used for follow-up Belgian Thyroid Club -39th meeting - Dec 3rd

30 Feasibility of standardization Phase II - Proof of concept FT4 Objective: demonstrate consistency in time of method comparisons against the reference measurement procedure (or surrogate ) (= sustainability) 1.2 Ratio Assay-mean/MS-mean Phase 2 Phase 1 A B C D E F G H I J K L M Belgian Thyroid Club -39th meeting - Dec 3rd 211 3

31 Feasibility of standardization Phase II - Proof of concept TSH 1.3 Ratio Assay-mean/Trimmed-mean Phase 2 Phase 1 D O M F B H J A K G C L N E Belgian Thyroid Club -39th meeting - Dec 3rd

32 Feasibility of standardization Standardization = recalibration on the basis of a method comparison Outcome of standardization Phase I & II FT4 Situation before and after recalibration Difference, means, all (%) Difference, means-recal, all (%) # FT4 ED ID-MS (pmol/l) FT4 ED ID-MS (pmol/l) Belgian Thyroid Club -39th meeting - Dec 3rd

33 Feasibility of standardization FT4 Between test CV before ( ) and after (Δ) recalibration 2 Between assay CV (%) FT4 ED-ID-MS (pmol/l) Belgian Thyroid Club -39th meeting - Dec 3rd

34 Feasibility of standardization Outcome of standardization Phase I & II TSH Situation before and after recalibration Difference Means (%) Difference Means (%) Trimmed Mean (miu/l) Trimmed Mean (miu/l) Belgian Thyroid Club -39th meeting - Dec 3rd

35 Feasibility of standardization TSH Between test CV before ( ) and after (Δ) recalibration 2 Between assay CV (%) TSH Trimmed mean (miu/l) Belgian Thyroid Club -39th meeting - Dec 3rd

36 Second conclusion Standardization is feasible Technical means are available Disseminate on activities/plans of the WG Implement (sustainable) standardization Belgian Thyroid Club -39th meeting - Dec 3rd

37 Transferability Way forward Belgian Thyroid Club -39th meeting - Dec 3rd

38 Way forward Transformation of WG-STFT into Committee Objective: involve a broader forum of stakeholders in preparation of the implementation phase Stakeholders (IVD manufacturers) Physicians and their patients Laboratory directors Professional societies Pharmaceutical companies Regulatory agencies Additional vehicles Medical journals Belgian Thyroid Club -39th meeting - Dec 3rd

39 Way forward Up to now, feasibility of standardization shown from method comparison with samples from apparently healthy individuals BUT What about the performance of the tests on clinical samples? Submit commercial tests to a method comparison with samples from different patient populations (hypo-, eu- and hyperthyroid patients) Project Phase III (212) Clinical samples, repository panels are needed! Belgian Thyroid Club -39th meeting - Dec 3rd

40 Phase III study Establish a strong physician laboratory interface January 21 Call to clinicians for: - Interest in joining the WG activities/discussions - Help with procurement of clinical samples/repository panels Several positive replies (Europe, Japan, USA), BUT: all restricted to interest in joining the WG activities Hindrances with regard to procurement of clinical samples - Approval by local ethical committees - Needed sample volume (15 ml serum/~ 3 ml blood) Route not further pursued Belgian Thyroid Club -39th meeting - Dec 3rd 211 4

41 Clinical samples: Phase III study FT4 n = 9: TSH n = 1 15 ml of serum per sample Commercial source for samples Contact person: Dr. Jim Boushell Address: 1 Commerce Way, Norton, MA 2766, USA Belgian Thyroid Club -39th meeting - Dec 3rd

42 Phase III study Belgian Thyroid Club -39th meeting - Dec 3rd

43 Phase III study Belgian Thyroid Club -39th meeting - Dec 3rd

44 Phase III study Criteria for enrolment of individuals Preferably, not under treatment. If treated, information on the type of treatment and when it has been started should be captured. Exclusion of patients diagnosed with a severe nonthyroidal illness (NTI) (state of dysregulation with abnormal levels of T3, T4, FT3 and/or FT4 although the thyroid gland does not appear to be dysfunctional). In practice, exclusion of critically ill patients suffering from CKD, liver cirrhosis, sepsis, trauma, advanced (active) malignancy, prolonged fasting/starvation, heart failure, MI, psychiatric disorder. Agreement on a fair cost price per donation (45 US$) Belgian Thyroid Club -39th meeting - Dec 3rd

45 Phase III study: status update (3/11/11) Population Details Target n Enrollment n TSH A1 <<<conc. 1 2 Hyperthyroid A2:.1-.1 miu/l* 1 1 A3:.1-.3 miu/l 1 9 B:.3-3. miu/l Eu 3 3 C1: 3.-5 miu/l Hypo 2 2 C2: >5 miu/l 2 2 FT4 D: > 2.2 ng/dl Hyper 3 5 E: ng/dl Eu 3 29 F:.2-.8 ng/dl Hypo 3 9 *Test specific Belgian Thyroid Club -39th meeting - Dec 3rd

46 Call of the Chair of WG-STFT Would you be willing to support us by active involvement in patient (and sample) recruitment? Belgian Thyroid Club -39th meeting - Dec 3rd

47 If yes,, contact me! Tel Belgian Thyroid Club -39th meeting - Dec 3rd