Paper Title
Diagnosis of Patients with Hypothyroidism Using Spectrochemical Analysis of Blood Sera

Abstract
Biochemical tests are critical in the management of patients with hypothyroidism (HT). Fourier Transfer Infrared (FTIR) which allows for global bio-fluid metabolic profiling may give more appropriate information by measuring a broad range of metabolic parameters in bio-fluid. Here we present the application of FTIR with chemometric analysis for the diagnosis of patients with hypothyroidism (HT). 26 patients and 26 healthy sex-matched individuals were prospectively recruited in this study. FTIR spectra were measured in serum samples. The most informative variables obtained by FTIR were selected by variable importance in the projection (VIP) value after creating an OPLS-DA model at three specific regions: 900-1200 cm-1, 1500-1700 cm-1, and 2800-3100 cm-1. The significance of each created model was validated by P-value (P<0.05) of CV-ANOVA. Multivariate analysis (OPLS-DA) of the FTIR data revealed the differences in the serum metabolic components of patients with hypothyroidism. OPLS-DA models revealed validation for 900-1200 cm-1 region (R2Y(cum)= 0.934; Q2(cum)= 0.514), 1500-1700 cm-1 region (R2Y(cum)= 0.726; Q2(cum)= 0.555), and 2800-3100 cm-1 region (R2Y(cum)= 0.959; Q2(cum)= 0.618) with P-value < 0.05 of CV-ANOVA. The results indicated that FTIR spectral biomarkers distinguish the serum of patients with hypothyroidism, for example, carbohydrates and nucleic acids, proteins (Amide I/Amide II), and lipids biomolecules. In summary, this work demonstrates that FTIR spectroscopy supported by Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) has the potential to become a fast and reagent-free method for biochemical characterization of serum that consequently could have a diagnostic significance in patients with hypothyroidism (HT). Keywords - Blood Serum Analysis, Chemometric Analysis, FTIR Spectroscopy, Hypothyroidism