What is the reliable initial screening test for hemochromatosis?

Hemochromatosis is a common inherited disorder of iron metabolism in which dysregulation of intestinal iron absorption results in deposition of excessive amounts of iron in parenchymal cells with eventual tissue damage and impaired function in a wide range of organs.It refers to a group of genetic diseases that predispose to iron overload, potentially leading to fibrosis and organ failure. Cirrhosis of the liver, diabetes mellitus, ahritis, cardiomyopathy, and hypogonadotropic hypogonadism are the major clinical manifestations.The degree of increase in total body iron stores can be assessed by (1) measurement of serum iron and the percent saturation of transferrin (or the unsaturated iron-binding capacity), (2) measurement of serum ferritin concentration, (3) liver biopsy with measurement of the iron concentration and calculation of the hepatic iron index and (4) magnetic resonance imaging (MRI) of the liver.The serum iron level and percent saturation of transferrin are elevated early in the course, but their specificity is reduced by significant false-positive and false-negative rates. Ref: Harrison&;s Textbook of Internal Medicine; 19th edition; Chapter 428; Hemochromatosis; Page no: 2517