Tests to determine iron levels
is a condition when iron levels are too high or too low for a person’s age or gender causing them to experience signs, symptoms or decreased ability to perform activities.
The most basic and essential tests to determine a person’s iron levels are:
hemoglobin (varies by age and gender)
serum iron (fasting is preferred, which is nothing by mouth after midnight and before lab work)
total iron-binding capacity (TIBC) or unbound-iron binding capacity (UIBC)
serum ferritin (varies by age and gender)
When any two of these results are out of range, an iron disorder is suspect. A person could be iron deficient and need to replenish depleted reserves. A person could have excessive amounts of iron. They could also have an iron imbalance because of inflammation. The chart provides a comparison of common iron disorders.
Transferrin-Iron Saturation Percentage Normal Range: 25-35%
Definitions and Descriptions
Hemoglobin measures functional iron. This iron delivers oxygen to cells and carries carbon dioxide away from cells.
Serum iron: is a test that measures the iron level in your blood.
Serum ferritin is often referred to as the body’s place for storing iron. Serum ferritin is elevated in conditions of iron overload, liver disease, alcohol abuse, nicotine product abuse (used to stop smoking) and in people who are sick with illnesses, which causes inflammation. SF is naturally elevated in newborns and infants. Serum ferritin is low in people who are iron deficient. Read about elevated serum ferritin in infants and newborns or about Anemia of Chronic Disease (ACD) also called anemia of inflammatory response.
Although ferritin does act as an “iron storage” facility, another key function of ferritin is to contain iron withholding the metal from harmful invaders. As part of the body’s natural defense system iron gets shuttled to ferritin. This function is activated and stepped up when inflammation is present in the body. Read more about The Iron Withholding Defense System and Anemia of Inflammatory Response in the Iron Library Reading Room.
Transferrin -iron saturation percentage (TS%)
. TS% is an indication of your ability to bind iron and transport it to various sites such as the bone marrow or liver. A fasting serum iron and IBC are needed to calculate the transferrin-iron saturation percentage (TS%)
Fasting* serum iron ÷ TIBC X 100%= transferrin-iron saturation percentage (TS%)
*Fasting is nothing by mouth (except water or prescribed medications) after midnight or at least 5 hours before tests.
A TS% above 45% (fasting) suggests iron loading, although elevated TS% could be a transient (passing) situation. Various foods and conditions can influence serum iron. You may wish to request a repeat fasting test with a stricter 72 hour pre-test avoidances of foods and substances: red meat, supplements, alcohol, vitamin C rich juices or high sugar foods/beverages. These items can increase iron absorption or alter results. A fasting TS% below 20 suggests iron deficiency or anemia of inflammatory response also called anemia of chronic disease.
More about iron binding and transport
Transferrin is a protein capable of combining with and transporting two atoms of iron.
Your body makes transferrin in relationship to your need for iron; when iron stores are low, transferrin levels increase, while transferrin is low when there is too much iron. Usually about one third of the transferrin is being used to transport iron. Because of this, your blood serum has considerable extra iron-binding capacity, which is the Unsaturated Iron Binding Capacity (UIBC). The TIBC is the total iron binding capacity; it equals UIBC plus the serum iron measurement. Some laboratories measure UIBC, some measure TIBC, and some measure transferrin.
UIBC measures the unsaturated binding capacity of transferrin.
A complete blood count (CBC) is highly recommended for anyone at risk for an iron disorder. See Complete Blood Count Explained in the Iron Library under articles..
Get the entire IRON picture
Hemoglobin gives you part of the iron picture, but to better determine iron status, you need to look at iron in several different ways. Besides hemoglobin which indicates how much iron you have in use, you need to know how much iron is bound to transferrin or unbound (UIBC or free) or contained in storage in ferritin. In some cases you may need to know how much iron is contained in bone marrow.
Hemoglobin, serum iron, TIBC or UIBC and serum ferritin are sufficient to establish a basic picture of one’s iron status, but in conditions of disease that may be due to blood cell production or cancers, other tests or procedures are needed to determine the cause for abnormal iron levels. These include (but are not limited to) a complete blood count with differential, zinc protoporphyrin (ZPP) immunological tests, hormone tests, retic count (reticulocyte count), C-reactive Protein (CRP), sedimentation rate (SED rate), B12 or folate levels, genetic testing, tissue biopsy, MRI, ultrasound, bone marrow aspiration, blood smears, urine or fecal sampling, scopes (endoscope or colonoscopy) and tests associated with specific diseases or conditions that can have anemia or iron overload as a symptom or consequence. To read about these specific tests or procedures, we suggest that you visit The National Library of Medicine MedlinePlus: www.nlm.nih.gov/medlineplus
To download PDF versions of our charts, visit the Iron Library. Here you can browse or use the search feature to find articles of interest, charts, forms, patient stories, links, diet and supplement information, treatment centers, read about upcoming events, become a volunteer, or make a donation. Our books are excellent resources for understanding iron disorders such as hemochromatosis, anemia of chronic disease, iron overload with anemia and iron deficiency.
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