LAT and coronary artery disorder: However, the lack of standardization means that LAT parameters vary from one centre to another: the acute oral LT4 dose (a fixed dose of 1000 μg vs. the patient’s normal daily dose), the measurement of TT4 or FT4, the equation used to calculate absorption, the threshold for a normal result (typically 60% or 65% of the administered dose at the 3 h time point), and the list of contraindications (mainly ischemic heart disease) [24, 149–152].