11/30/21 blood test showed tsh level 4.693, followup from same lab 3/15/22 gave tsh value 1.723. both taken early morning second test fasted overnight first test had small amount of food before. is that much change is such a short time normal?

Eating tends to lower TSH but other thyroid parameters may not be affected. I must confess that I don't ask patients to fast before a thyroid panel is drawn, but I never only order a TSH, but have the entire thyroid panel drawn every 3 months if the patient is on treatment. For screening purposes I feel a TSH, T4 & T3 suffice and am satisfied if all are within normal limits.