How iron status is measured?

 Biochemical assessment of iron:

Iron sources

Iron is a vital mineral element naturally present in many food items. Apart, many iron supplement available in market . Dietary iron exists in two forms; heme and non- heme . Plant based food and other iron fortified product contains mostly no-heme iron, whereas, animal source like mutton, beef,  sea food , dairy and poultry contain both form of iron.

 Owning to structural differences, absorption of heme-iron is significantly more(15-35%)as compared non- heme iron(2-20%). Thus, vegetarian may need to consume twice as much dietary iron is compared to non-vegetarian to obtain an adequate amount of iron.

 Iron is a vital element in the formation of blood, and about 70%of the body iron exists in erythrocytes in the form of hemoglobin6% of the body iron is constituent of proteins necessary for energy metabolism and respiratory functions. Iron serve as a component of enzymes involved in collagen and neurotransmitters synthesis.

 Iron is also required for the proper function of the immune system. About 25%of iron is human body is stored in the form of ferritin .Average adult male have iron stores ranging from 600-1000mg (for about 3 years)while female have about 200-300 mg of iron sores in their body(for about 6 month).

Serum Ferritin:

Serum ferritin is a marker of stored iron in the body. It's usually the first line of investigation in evaluating iron status. Low ferritin levels indicate depleted iron stores, suggestive of iron deficiency. However, ferritin is also an acute-phase reactant, meaning its levels can increase in response to inflammation, infection, or malignancy, which can complicate the interpretation.

Transferrin Saturation (TSAT):

TSAT is a measure of the proportion of transferrin, a protein that transports iron in the blood, that is saturated with iron. Low TSAT (<20%) often indicates iron deficiency, whereas a high TSAT (>45%) can suggest iron overload conditions, such as hemochromatosis.

Serum Iron and Total Iron Binding Capacity (TIBC)L:

Serum iron measures the amount of circulating iron bound to transferrin. TIBC estimates the maximum amount of iron that transferrin can carry. Low serum iron and high TIBC can indicate iron deficiency, while high serum iron and low TIBC can indicate iron overload.

Soluble Transferrin Receptor (sTfR):

sTfR is a relatively newer marker of iron status. It increases when there's an iron deficiency in the body's tissues. This test can be particularly useful when ferritin results are difficult to interpret due to inflammation or infection.

Full Blood Count (FBC):

The FBC can reveal signs of anemia (low hemoglobin levels), which can occur as a result of iron deficiency. The red cell indices, including mean cell volume (MCV), mean cell hemoglobin (MCH), and mean cell hemoglobin concentration (MCHC), can also provide clues to the presence of iron deficiency anemia, typically presenting as microcytic, hypochromic anemia.

Deficiency of iron;  

It is the one 0f the most prevalent nutritional deficiency in females and children. Chronically low iron intake may result in the depletion of iron stores. Further decrement can cause erythropoiesis which lead to iron deficiency anemia. Iron deficiency anemia is also known as microcytic anemia(hypochromic anemia).

 Apart from low dietary intake, inflammatory bowel disease, malabsorption and increased iron requirement during pregnancy can lead to anemia. Certain chromic diseases such as AIDS, kidney diseases , cancer, rheumatoid arthritis, and some inflammatory diseases may interfere with iron absorption leading to iron deficiency anemia.

Measurement of iron status;

To evaluate iron- deficiency anemia , hematocrit and hemoglobin concentration are commonly observed; lowered value being indicative of iron deficiency anemia However, both indicator are neither sensitive nor specific.

 Serum ferritin (the primary form of iron stored in liver, spleen and bone marrow) is another indicator of iron reserve, Approximately, 30% of the body iron is in the stored from. Once iron stores start to deplete, tissues ferritin level being to decrease. 

Therefore, this test could be a sensitive indicator for iron status. For conformation, mean corpuscular volume(MCV) and mean corpuscular hemoglobin (CH) of RBCs are tested.

Conclusion:

The biochemical assessment of iron involves a series of tests, with each providing different information about the body's iron stores, transport, and functionality. Understanding the results requires an appreciation for the complexities of iron metabolism and the multiple factors that can affect these tests. With the right interpretation, these tests can effectively guide the diagnosis and management of conditions related to iron status.

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