Iron Total (Fe)

Sample for Iron Total (Fe)

1. The test is done on the serum of the patient.
2. Collect the blood sample in the morning.
3. Avoid food at least 12 hours before giving the blood.

Purpose of the test (Indications) for Iron Total (Fe)

1. This test is done to evaluate the concentration of iron in the body.
2. This test will give information about the deficiency or overdose of iron.
3. It is advised in the workup of anemia.

Precautions  for Iron Total (Fe)

1. Avoid hemolysis because iron of the RBCs may increase the iron level.
2. Please get the history of blood transfusion in a recent period of time.
3. The hemolytic disease may give a falsely high value.
4. The Recent History of iron-containing food or medication will affect the result.
5. Get the history of drugs that may decrease the value, like chloramphenicol, methicillin, colchicine, ACTH, testosterone, and deferoxamine.
6. Get the history of drugs that may increase the level of iron, like Estrogen, dextran, ethanol, iron preparation, methyldopa, and oral contraceptives.

Pathophysiology of Iron Total (Fe)

Iron distribution in the body:

1. Iron is just like a trace element present in the body. Normally there is a very small amount of iron in the cells, plasma, and other body fluids.
2. Iron is distributed in the body in different compartments like:
   1. Hemoglobin (70 % of the body).
      1. Approximately 2.5 G of iron is present in hemoglobin.
   2. Tissue iron.
   3. Myoglobin.
   4. Labile pool.
   5. The other 30% is present in the form of ferritin and hemosiderin.

Iron storage sites

3. Iron in the males and females is in different concentrations.

Metabolism of iron (Iron Total (Fe):

1. In plasma total amount of 2.5 mg of iron is present.
2. The iron is taken in the ferric form (Fe⁺⁺⁺) in the diet and changes to the ferrous form (Fe⁺⁺) in the stomach by the  Hydrochloric acid.
3. It is then absorbed mainly in the small intestine.
4. The leftover is excreted in the feces.
5. Iron combines with the β-globulin and forms Transferrin.
6. Iron available in the blood is used by the RBCs in the bone marrow.
   1. 60% stored in the reticulum cells of bone marrow, liver, and spleen as Ferritin, and 40% as hemosiderin.
7. It then combines with apoferritin, the protein that makes a ferritin complex.
8. Iron is stored as ferritin in the body.

9. Now Ferric ions combine with the Transferrin, which is synthesized in the liver.
10. Transferrin helps:
    1. Make an insoluble iron form.
    2. It prevents iron-mediated free radical toxicity.
    3. This facilitates iron transport into the cells.

Transferrin and Transport of iron:

1. Plasma protein apo-transferrin transports iron from one organ to another organ.
2. This apo-transferrin is beta 1-globulin. It has two sites to attach to the iron.
3. Apoferritin + Fe complex is called Transferrin.

Transferrin and binding of an iron molecule

Ferritin:

1. It is the storage form of iron = Apoferritin shell + ferric oxyhydroxide FeO(OH).
2. Ferritin is found almost in all cells of the body.
3. Iron is supplied in the diet, and 10 % of ingested iron is absorbed in the small intestine and transported to plasma.
4. Iron in plasma is bound to β-globulin called  Transferrin. It enters the bone marrow and incorporates into developing red blood cells, becoming part of the hemoglobin.
5. Ferritin in liver cells and macrophages is the reserve for hemoglobin and another hemoprotein.
6. Men’s total ferritin store is 800 mg.
   1. Women’s total ferritin stored varies from 0 to 200 mg.
7. Ferritin concentration decreases before there is a drop in the hemoglobin and changes in the RBCs morphology or serum iron concentration.

Hemosiderin:

1. It is also stored in the form of iron.
2. This is aggregated, partially deproteinized ferritin.
3. This is insoluble in the aqueous solution.
4. This is found in the liver cells, spleen, and bone marrow.
5. On-demand, it is released slowly.
6. Iron is needed for the formation of hemoglobin.

Abnormal level of iron causes (Complications of iron overload):

1. Iron deficiency causes iron deficiency anemia.
2. Overdose causes hemochromatosis.
3. Iron overload is seen in:
   1. Hemosiderosis.
   2. Hemochromatosis is seen as an injury to the organs, and there are degeneration and fibrosis.
   3. Sideroblastic anemia is due to iron overload, and no exact mechanism is known.
4. 70% of iron is found in the hemoglobin of RBCs.
   1. 30% of iron is stored in the form of :
      1. Ferritin.
      2. Hemosiderin.
5. Iron is supplied to the body through the diet. Where 10% of iron is absorbed in the small intestine and delivered to the blood.
6. Transferrin = Iron + globulin (Iron is bound to globulin).
7. Transferrin goes to the Bone marrow and Forms hemoglobin.
8. Serum iron is iron bound to transferrin.

Normal Iron Total (Fe)

Source 1 

• To convert into SI unit x 0.179 = µmol/L

Source 2

• Male = 80 to 180 µg/dL.
• Female = 60 to 160 µg/dL.
• Newborn = 100 to 250 µg/dL.
• Child = 50 to 120 µg/dL.

Normal urine iron

• 100 to 300 ng/24 hours of urine

Iron level in liver tissue

• 530 to 900 µg/g dry weight of the liver tissue

Lab tests the significance of Iron Total (Fe):

1. For iron deficiency, measurement of total iron, iron-binding capacity, and transferrin saturation should not be requested.
2. The above tests are only useful in screening chronic iron overload diseases.
   1. Confirmation and monitoring of acute iron poisoning in children.

Increased Serum Iron Total (Fe) level is seen in:

1. Hemolytic anemias.
2. Hemochromatosis or hemosiderosis.
3. Multiple transfusions.
4. An overdose of iron therapy.
5. Nephritis.
6. Liver damage and acute hepatitis.
7. Vit.B6 deficiency.
8. Lead poisoning.
9. Acute leukemias.
10. Iron overload syndrome.

Decreased serum Iron Total (Fe) level is seen in:

1. Iron deficiency anemia.
2. Inadequate absorption of iron.
3. Chronic blood loss.
4. Paroxysmal nocturnal hematuria.
5. Pregnancy is mostly in the third trimester.
   1. There is a 30% decrease in iron after every menstrual cycle.
6. Chronic diseases, e.g., chronic infections, autoimmune diseases like SLE, and rheumatoid arthritis.
7. Remission of pernicious anemia.
8. Inadequate absorption from the intestine is like malabsorption.
9. Short bowel syndrome.
10. Malignancies.
11. Chronic hematuria.

• Note: Serum iron should be advised along with total iron-binding capacity and transferrin.
  Please see more details on Total iron-binding capacity and Transferrin.

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