Having tpo antibody 17 and thyroglobulin <20 confirms hashimoto's or not? i had tsh 4.67 which reduced to 2.61 in 18 days after taking levothyroxine.

Depends on TPO assay: Hi. It depends on the normal range for TPO antibodies in that assay. Your thyroglobulin antibodies are undetectable, and that's normal. So without know the normal range, I can't say. If your TSH fell from 4.67 to 2.61 in 18 days, it will be lower still by the time that l-thyroxine dose reaches steady state in your body after 5-7 weeks of therapy.