- The test is done on the serum of the patient.
- Collect the blood sample in the morning.
- Avoid food at least for 12 hours before giving the blood.
Purpose of the test (Indications)
- This test is done to evaluate the concentration of iron in the body.
- This test will give information about the deficiency or overdose of iron.
- This is advised in the workup of anemia.
- Avoid hemolysis because iron of the RBCs may increase the iron level.
- Please get the history of blood transfusion in the recent period of time.
- The hemolytic disease may give false high value.
- The Recent history of iron-containing food or medication will affect the result.
- Get the history of drugs which may decrease the value like chloramphenicol, methicillin, colchicine, ACTH, testosterone, and deferoxamine.
- Get the history of drugs which may increase the level of iron like Estrogen, dextran, ethanol, iron preparation, methyldopa and oral contraceptives.
- Iron is just like trace element present in the body. Normally there is a very small amount in the cells, plasma, and other body fluids.
- Iron is distributed in the body in different compartments like:
- Hemoglobin (70 % of the body).
- Tissue iron.
- Labile pool.
- Other 30% is present in the form of ferritin and hemosiderin.
- Approximately 2.5 G iron is present in hemoglobin.
- In plasma total amount of 2.5 mg iron is present.
- The iron is taken as ferric form and it changes to the ferrous form in the stomach by the Hydrochloric acid.
- It is then absorbed mainly in the small intestine.
- The leftover is excreted in the feces.
- It then combines with the apoferritin which the protein and make a complex of ferritin.
- Iron is stored as ferritin in the body.
- Now Ferric ions combine with the Transferrin which is synthesized in the liver.
- Transferrin helps:
- Make iron in soluble form.
- It prevents iron-mediated free radical toxicity.
- This facilitates iron transport into the cells.
- Transport of iron
- Plasma protein apo-transferrin transport iron from one organ to another organ.
- This apo-transferrin is beta 1-globulin. It has two sites to attach to iron.
- Apoferritin + Fe complex is called Transferrin.
- Ferritin is the storage form of iron = Apoferritin shell + ferric oxyhydroxide FeO(OH).
- Ferritin is found almost in all cells of the body.
- Iron is supplied in the diet and 10 % of ingested iron is absorbed in the small intestine and transported to plasma.
- Iron in plasma is bound to globulin called Transferrin enters bone marrow incorporate into hemoglobin.
- Ferritin in liver cells and macrophages is the reserve for hemoglobin and another hemoprotein.
- Men total ferritin store is 800 mg.
- Women total ferritin stored varies from 0 to 200 mg.
- Ferritin concentration decreases before the is a drop in the hemoglobin, and changes in the RBCs morphology or serum iron concentration.
- Hemosiderin is also stored form of the iron.
- This is aggregated, partially deproteinized ferritin.
- This is insoluble in the aqueous solution.
- This is found in the liver cells, spleen and bone marrow.
- On demand, it is released slowly.
- Iron needed for the formation of hemoglobin.
- Abnormal level of iron causes:
- Iron deficiency anemia.
- Overdose causes hemochromatosis.
- Iron overload is seen in:
- Hemochromatosis, which is seen as an injury to the organs and there are degeneration and fibrosis.
- Sideroblastic anemia is due to iron overload and no exact mechanism is known.
- 70% of iron is found in the hemoglobin of RBCs.
- 30% of iron stored in the form of :
- Iron is supplied to the body in the diet. Where 10% of iron is absorbed in the small intestine and delivered to blood.
- Transferrin = Iron + globulin (Iron is bound to globulin).
- Transferrin goes to Bone marrow Form hemoglobin.
- Serum iron is iron bound to transferrin.
||100 to 250
||40 to 100
||50 to 120
||280 to 2550
|Fatally poison child
||65 to 175
||50 to 170
- To convert into SI unit x 0.179 = µmol/L
- Male = 80 to 180 µg/dL.
- Female = 60 to 160 µg/dL.
- Newborn = 100 to 250 µg/dL.
- Child = 50 to 120 µg/dL.
Lab tests significance
- Measurement of total iron, iron binding capacity and transferrin saturation, should not be requested for iron deficiency.
- The above tests are only useful in the screening of chronic iron overload diseases.
- Confirmation and monitoring of acute iron poisoning in the children.
Increased Serum Iron level is seen in:
- Hemolytic anemias.
- Hemochromatosis or hemosiderosis.
- Multiple transfusions.
- An overdose of iron therapy.
- Liver damage and acute hepatitis.
- Vit.B6 deficiency.
- Lead poisoning.
- Acute leukemias.
- Iron overload syndrome.
Decreased serum Iron level is seen in:
- Iron deficiency anemia.
- Inadequate absorption of iron.
- Chronic blood loss.
- Paroxysmal nocturnal hematuria.
- Pregnancy mostly in the third trimester.
- There is a 30% decrease in the iron after every menstrual cycle.
- Chronic diseases e.g. chronic infections, autoimmune diseases like SLE and rheumatoid arthritis.
- Remission of pernicious anemia.
- Inadequate absorption from the intestine like malabsorption.
- Short bowel syndrome.
- 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.
Possible References Used
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