Assessment of thyroid function during postpartum period with total thyroxine and total triiodothyronine levels measured by LC-MS/MS

İngilizce (OpenAlex)

Background: Assessment of thyroid function is important during postpartum period. However, measurements of total thyroxine (TT4) and total triiodothyronine (TT3) levels by immunoassays are mostly inaccurate during pregnancy and postpartum period, as immunoassays are interfered by hormone-binding proteins. LC-MS/MS is known to be selective and specific for the analysis of endocrine hormones and can be utilized for the analysis of TT4 and TT3. The aim of this study is to evaluate the reliability of TT4 and TT3 results measured by LC-MS/MS during postpartum period.Materials and Methods: Serum samples (n = 358) were obtained within postnatal 48 hr from participants. TT4 and TT3 levels were measured by LC-MS/MS method (TT4MS and TT3MS). Levels of free T4 (FT4), free T3 (FT3) and thyroid-stimulating hormone (TSH) were measured by immunoassay methods (FT3IA, FT4IA, and TSHIA).Results: Statistically significant correlation was found between TSHIA and TT4MS (r = −0.13 and P = 0.01), whereas no correlation was detected between TSHIA and FT4IA, TT3MS or FT3IA.Conclusions: Significant negative correlation between TT4MS and TSHIA, and lack of correlation between FT4IA and TSHIA indicates that TT4MS measured by LC-MS/MS could be a more reliable parameter in the diagnosis of thyroid deficiency during postpartum period.