How are you getting your TPO antibodies measured?

Both endocrinologists I’ve seen now will not order lab tests for me to see my antibody levels. They say it doesn’t matter what the levels are once I’ve been diagnosed with Hashimoto’s. What matters is my TSH they say, which is normal now that I’m on tirosint. So why is everyone here always talking about antibody levels going up and down and how are you getting your doctor to check those all the time? I’ve never had mine checked since the first time since they refuse now!