To determine if your wife's Thyrox (thyroxine) dosage needs to be adjusted, her doctor must review the specific numbers from her new blood test, particularly her TSH (Thyroid Stimulating Hormone) level. If her TSH is within the normal target range, her current 50 mcg dose is likely perfect. If her levels are slightly high or low, her doctor will easily and safely fine-tune her dose to keep her healthy. Dosage adjustments are a very routine and normal part of managing a thyroid condition. Please share the laboratory reports with her doctor for a precise decision, and do not alter her dose without medical guidance.