Examinando por Materia "Thyrotropin"

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    Detection of macromolecules of Thyroid-Stimulating Hormone (TSH) Using Polyethylene Glycol (PEG) in Serum Samples Suspected of Subclinical Hypothyroidism
    (Universidad Privada Norbert Wiener, 1905-07-07) Lazarte Paralfo, Tuanny Antuanet; Punchin García, Elsa Julieta
    The thyroid-stimulating hormone (TSH) presents molecular heterogeneity, and commercial immunoassays use different monoclonal antibodies, leading to differences when TSH is part of a complex with immunoglobulin or macroTSH. MacroTSH is biologically inactive but remains reactive in immunoassays. Objective: To determine the presence of macroTSH using polyethylene glycol 6000 precipitation at 25% in patients suspected of having subclinical hypothyroidism. Study type: Descriptive, cross-sectional, prospective, non-probabilistic. Materials and methods: 192 anonymous samples were studied, measured for TSH using two immunoassays (direct and indirect chemiluminescence), before and after precipitation. The formula according to Hattori was applied to calculate the percentage of macroTSH recovery. Results: The cutoff point used was 75% probability of macroTSH presence, with 6 positive samples (3.13%), of which two were identified by both methods, and the remaining four were only positive for direct chemiluminescence. Both methods showed a high correlation (0.95) for TSH concentrations before and after precipitation. Conclusions: There was a higher probability of macroTSH presence when using recovery percentage, with six samples precipitated using polyethylene glycol. Direct chemiluminescence was more sensitive in detecting macroTSH. The polyethylene glycol precipitation technique proved to be effective, fast, cost-effective, and easy to implement in routine clinical laboratories for macroTSH detection.