The parameters that is helpful in the assessment of the problem of IDD ranges from simple clinical signs through analysis of biological fluids like urine, serum to radioactive iodine uptake studies. Depending upon the infrastructural facilities available, the following indicators may be employed.
Serum thyroxin T 4 level and pituitary thyro tropic harmone
Serum TSH level
Prevelance of neo-natal chemical hypothyroidism.
Iodine levels in drinking water. (less than 2mg per lit)
In large scale community surveys clinical examination of individuals for prevalence of goiter and cretinism and laboratory estimation of urinary iodine excretion and iodine in water, form the important investigations.
If in an area, the total goiter rate (TGR) =Number with goiter grade 1 +2 among the children aged six to twelve years is equal to or more than 5% , that area is said to be endemic (WHO/UNICEF/ICCID/2001).