Table 1.

Existing Schemes Proposed in the Literature for the Estimation of LT4 Requirements after Thyroidectomy

Author/location	Formula or Scheme
Cunningham et al. 1984/New Haven, Connecticut	$$\begin{gathered} \text{LT}4\ast \text{dose}(\mu \mathrm{g}/\text{day})=3.4\times {\text{LBM}}^{†}-11; \\ \text{LBM}(\text{male})=(79.5-0.24\times \text{weight}-0.15\times \text{age})\times \text{weight}/73.2 \\ \text{LBM}(\text{female})=(69.8-0.26\times \text{weight}-0.12\times \text{age})\times \text{weight}/73.2 \end{gathered}$$
Olubowale et al. 2005/Chesterfield, United Kingdom	$$\begin{gathered} \text{LT}4\text{dose}(\mu \mathrm{g}/\text{day})=100\text{if}\text{weight}<53 \\ =125\text{if}53\le \text{weight}\le 86 \\ =150\text{if}86<\text{weight}\le 108 \\ =175\text{if}\text{weight}>108 \end{gathered}$$
Mistry et al. 2011/Hull, United Kingdom	$\text{LT}4\text{dose}(\mu \mathrm{g}/\text{day})=(0.943\times \text{weight})+(-1.165\times \text{age})+125.8$
Ojomo et al. 2013/Madison, Wisconsin	$\text{LT}4\text{dose}(\mu \mathrm{g}/\text{day})=(-0.018\times {\text{BMI}}^{‡}+2.13)\times \text{weight}$
Jin et al. 2013/Cleveland, Ohio	$\text{LT}4\text{dose}(\mu \mathrm{g}/\text{day})=1.5\times \text{weight}$
Di Donna et al. 2014/Rome, Italy	LT4 dose (μg/kg/day) =	BMI	≤ 23	23–28	> 28
		Age
		≤ 40	1.8	1.7	1.6
		> 40–55	1.7	1.6	1.5
		> 55	1.6	1.5	1.4
Elfenbein et al. 2015/Madison, Wisconsin	LT4 dose (μg/kg/day) =		Male		Female
		BMI
		< 21	2.1		1.8
		22–26	1.9		1.7
		27–32	1.7		1.6
		33–40	1.5		1.4
		>40	1.3		1.2

^*LT4 = levothyroxine;

^†LBM = lean body mass;

^‡BMI = body mass index. All weights are in kg.