As a screening test for iron deficiency or chronic total-body iron overload (such as hemochromatosis), an overnight fasting sample is best.  If checking  for acute iron poisoning,  a diagnostic baseline sample  taken at any time prior to treatment is optimal. Screening programs to detect iron overload much more frequently identify cases of iron deficiency (low iron)...a situation which demands diagnostic work up without any undue delay (there may be a serious & manageable reason)! An "iron profile" screen for serum iron and total iron-binding capacity (TIBC...STS serum transferrin saturation) gives a result that reflects the percentage iron saturation of the iron-binding sites on the transferrin protein (iron carrier protein). A percentage saturation >55% is cause to look further for iron overload. This is a much more specific screening test than serum ferritin (many other causes of elevated ferritin especially are a non-fasting sample & also other liver disease, inflammation, recent multiple transfusions, and some cancers can elevate into the 1000s & not necessarily indicate "iron overload"). Genetics: most cases of true genetic hemochromatosis are identified with a 3-marker panel for HFE by PCR for C282Y, H63D, and S65C. In our lab, it is orderred as "genetic testing for hemochromatosis". ARUP DX decision tree HERE.

When we see siderosis in tissues removed for other reasons (such as siderotic corpora albicantia in ovaries [L11-718]), it may be an opportunity to suggest an"iron profile" screen & check for occult systemic siderosis.

• Insufficient iron intake

• Insufficient iron  absorption

• Blocked iron utilization  into red blood cells

• Increased outgo due to either increased loss or increased metabolic usage

• excess vitamin C intake in a  chronically iron-overloaded individual (can produce a toxic...even lethal...overdose)

• whole body overloaded with iron (chronic hemochromatosis; hemosiderosis; systemic siderosis of uncertain etiology)
  

  [is liver biopsy staging advisable?]

•  Normal Pregnancy (physiological increase)