Objectives: We systematically investigated normally or
subclinically increased thyroid stimulating hormone (TSH)
values associated with unexpectedly increased thyroxine
(FT4) and free triiodothyronine (FT3) in findings of patients
without any thyroid disease. Moreover, we looked for
alternatives to overcome such states with an improved
diagnostic procedure and to investigate the pathogenetic
background of the respective patients.
Methods: Samples with TSH concentrations within the
range of 0.4–10 mU/L combined with increased concentrations
of FT4 (n=120; Cobas, Roche) were collected over a
period of around six years. Cobas FT4 results were
compared with measurements from Liaison (DiaSorin) and
Architect (Abbott) FT4 assays. For further validation all
samples were measured for total thyroxine (TT4) (Cobas,
Roche). Finally, FT3 and TT3 as complementary parameters
were measured in samples with leftover material. To overcome
potential analytical disturbances from stimulating
heterophilic antibodies, we used heterophilic blocking
tubes (HBTs).
Results: From the 120 samples with increased FT4 concentrations
by Cobas, 51/120 were also increased by
Liaison, and 26/120 by Architect. However, the measurement
of TT4 indicated only n=10/120 increased values. The
number of increased FT3 (n=71) measurements was higher
in Architect>Cobas>Liaison (28>27>9). TT3 levels of 70/71
samples were within the reference interval. HBTs were
inappropriate to reduce unspecific immunoreactivity in our
samples. No clear pathogenetic background could be
elucidated in the anamnesis of individual patients.
Conclusions: To overcome dubious constellations of TSH,
FT4, and FT3, it is helpful to measure TT4 and TT3 for
control or to use an immunoassay with an alternative assay
design for the respective parameters.:I. Abkürzungsverzeichnis 4
I. Einleitung 5
1.1 Hintergrund 5
1.2 Regelkreis 7
1.3. Methodik zur Diagnostik von Schilddrüsenhormonen 8
1.5. Störfaktoren 9
1.6 Fragestellungen/Ziele 11
2 Publikationsmanuskript 13
3 Zusammenfassung der Arbeit 23
4 Literaturverzeichnis 27
II Anhang 37
III Darstellung des eigenen Beitrags 40
IV Erklärung über die eigenständige Abfassung der Arbeit 41
V Curriculum vitae 42
VI Publikationen 44
VII Danksagung 45
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:90833 |
| Date | 10 April 2024 |
| Creators | Külz, Martin |
| Contributors | Universität Leipzig |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | German, English |
| Detected Language | English |
| Type | info:eu-repo/semantics/acceptedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 10.1515/cclm-2021-1211 |
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