Hyponatremia is associated with an increased risk of death. The economic costs of hyponatremia are estimated at $2.6 billion in the United States. Signs and symptoms of hyponatremia include nausea and vomiting, headache, short-term memory loss, confusion, lethargy, fatigue, loss of appetite, irritability, muscle weakness, spasms or cramps, seizures, and decreased consciousness or coma. The presence and severity of signs and symptoms are related to the level of salt in the blood, with lower levels of plasma sodium associated with more severe symptoms. However, emerging data suggest that mild hyponatremia (plasma sodium levels at 131–135 mmol/L) is associated with numerous complications
Serum iron in other molecules in cells throughout the body. None of this iron is directly accessible by testing the serum. However, some iron is circulating in the serum. Transferrin is a molecule produced by the liver that binds one or two iron(III) ions, i.e. ferric iron, Fe; transferrin is essential if stored iron is to be moved and used. Most of the time, about 30% of the available sites on the transferrin molecule are filled. The test for serum iron uses blood drawn from veins to measure the iron molecules that are bound to transferrin, and circulating in the blood. The