Assessment of Thyroid Function: Towards an Integrated Laboratory - Clinical Approach

摘要: Laboratory assessment of thyroid function is now often initiated with a low pre-test probability, by clinicians who may not have detailed knowledge current methodology or testing strategies. Skilled laboratory staff can significantly enhance the choice appropriate tests and accuracy clinical response; such involvement requires both training relevant information from clinician. Measurement serum stimulating hormone (TSH) concentration an assay adequate sensitivity cornerstone testing; for untreated populations at risk primary dysfunction, normal TSH rules out abnormality high degree certainty. However, in several important situations, most notably pituitary abnormalities early treatment give misleading indication status. An abnormal alone never basis initiation treatment, which should be based on typical relationship between trophic target gland hormones, estimate free thyroxine (T4). Six basic assumptions, some clinical, laboratory-based, need to considered, together limiting conditions, reliable use this relationship. Current methods T4 estimation remain imperfect, especially during critical illness. Diagnostic approach differs initial diagnosis follow-up treated dysfunction. In triiodothyronine (T3) also required, but T3 lacks hypothyroidism, has poor specificity non-thyroidal Where results are anomalous, atypical findings resolved attention context, without further investigation.