Serum transferrin and transferrin saturation are commonly used as screening for haemochromatosis. Transferrin binds iron and is responsible for iron transport in the blood.[27] Measuring transferrin provides a crude measure of iron stores in the body. Fasting transferrin saturation values in excess of 45% for males or 35% in premenopausal women (i.e. 300 ng/L in males and 200 ng/L in females) are recognized as a threshold for further evaluation of haemochromatosis.[10][28] Transferrin saturation greater than 62% is suggestive of homozygosity for mutations in the HFE gene.[29] Serum Ferritin: Ferritin, a protein synthesized by the liver is the primary form of iron storage within cells and tissues. Measuring ferritin provides another crude estimate of whole body iron stores though many conditions, particularly inflammation (but also chronic alcohol consumption, non-alcoholic fatty liver disease and others), can elevate serum ferritin - which can account for up to 90% of cases where elevated levels are observed.[4] Normal values for males are 12–300 ng/ml (nanograms per millilitre) and for female, 12–150 ng/ml.[26][30] Serum ferritin in excess of 1000 nanograms per millilitre of blood is almost always attributable to haemochromatosis. Other blood tests routinely performed: blood count, renal function, liver enzymes, electrolytes, glucose (and/or an oral glucose tolerance test (OGTT)).