B-114 Reference interval (RI) estimation for TSH in adults using an indirect method with unsupervised machine learning tool and R programming language

Abstract Background Thyroid-stimulating hormone (TSH) plays a fundamental role in regulating thyroid hormones T3 (triiodothyronine) and T4 (thyroxine). Understanding TSH test results is essential for effective management of thyroid disorders and depends, among other factors, on establishing specific reference intervals (RI) for the population being served. We aimed to estimate the reference intervals for TSH in the adult population served by a large diagnostic network in Brazil. Methods We employed data mining followed by estimation using an indirect method through the LabRI™ algorithm with parametric, non-parametric, and robust statistical treatments for outlier exclusion, a series of algorithms programmed in R Language. Included were TSH values from outpatients, aged 20 to 60 years, both sexes, from two analytical platforms. Used as a comparative RI recommended by the American Thyroid Association (ATA, 2014). Data were extracted from the Data Lake, from January to December 2022, from two laboratories in Brazil. Exclusion criteria: samples from hospital sources and referral laboratories; pregnant; some laboratory tests correlated with de TSH test; samples from patients using thyroid hormone and medications that may interfere with hormonal function and TSH laboratory analysis. Results After exclusion criteria, the sample totaled 26,909 adults of both sexes. After excluding 2.24% outliers, the estimated RI was 0.67-4.26 mIU/L, with the comparative RI chosen for this study being the one recommended by ATA of 0.40-4.00 mIU/L. The RI obtained in our study was similar to the Canadian RI harmonization study for TSH (0.60-4.48 mIU/L). Conclusions We estimated the RI, harmonized between Roche and Siemens platforms, to be 0.67-4.26 mIU/L. The RI obtained by the LabRI™ tool is equivalent to the Adeli study (2023) and is under discussion by the company's endocrinology committee for whether to use the estimated RI from our internal study or the one recommended by ATA (2014) in reports.