TPO and hypothyroidism: However, thyroid function tests were abnormal, with low T4 7.0 (9.0-19.6 pmo/L), low T3 3.0 (5.1-10.0 pmol/L), and high thyroid-stimulating hormone (TSH) 12.6 (<6.0 mU/L) with no evidence of anti-thyroid peroxidase antibody (TPO) or thyroid stimulating hormone receptor antibodies (TRab) pointing to the presence of hypothyroidism for which Levothyroxine was started.