Lab 7 Serum Iron Picture Laboratory Evaluation of

Lab 7 Serum Iron Picture

Laboratory Evaluation of Iron § Disorders of iron metabolism are evaluated primarily by : 1. packed cell volume 2. Hemoglobin & red cell count and indices 3. Total iron and TIBC, percent saturation, transferrin, and ferritin

1. Total Iron-Binding Capacity § Total iron-binding capacity (TIBC) refers to the amount of iron that could be bound by saturating Transferrin and other minor iron-binding proteins present in the serum or plasma sample. § Typically, about 1/3 of the iron-binding sites on Transferrin are saturated. § TIBC is determined by adding sufficient Fe+3 to saturate the binding sites on Transferrin, with the excess iron removed by addition of Mg. CO 3 to precipitate any Fe+3 remaining in solution.

§ After centrifugation to remove the precipitated Fe+3, the supernatant solution containing the soluble iron bound to proteins is analyzed for total iron content. § TIBC ranges from around 250 to 425 mg/d. L. § Transferrin or TIBC is increased in iron deficiency and decreased in iron overload and hemochromatosis. § Transferrin (TIBC) may also be decreased in chronic infections and malignancies

2. Total Iron Content (Serum Iron) § Measurement of serum iron concentration refers specifically to the Fe+3 bound to transferrin and not to the iron circulating as free hemoglobin in serum. § The specimen may be collected as serum without anticoagulant or as plasma with heparin. § Oxalate, citrate, or EDTA all are unacceptable anticoagulants as they binds Fe ions. § Early morning sampling is preferred because of the diurnal variation in iron concentration.

§ Specimens with visible hemolysis should be rejected. § Spectrophotometric determinations have been adapted to automated analysis. These procedures generally have the following steps: Fe+3 is released from binding proteins by acidification, reduced to Fe+2 by ascorbate or a similar reducing agent, and complexed with a color reagent such as ferrozine, ferene, or bathophenanthroline.

3. Percent Saturation § TS% is an indication of your ability to bind iron and transport it to various sites such as the bone marrow or liver. § The percent saturation “Transferrin saturation”, is the ratio of serum iron to TIBC * 100%. § Normal range is approximately 20% to 50%, but it varies with age and sex § Transferrin saturation is a more useful indicator of iron status than just iron or TIBC alone.

4. Transferrin § Transferrin is a protein capable of combining with and transporting two atoms of iron. § Transferrin is measured by immunochemical methods such as nephelometry. § It is primarily monitored as an indicator of nutritional status. § As a negative acute-phase protein, its concentration decreases in inflammatory conditions.

5. Ferritin § Serum ferritin is often referred to as the body’s place for storing iron. § Ferritin is measured in serum by immunochemical methods, such as (IRMA), (ELISA), and chemiluminescent techniques. § Several manufacturers provide kits for measuring serum ferritin by either manual or automated means. § Ferritin is decreased in iron-deficiency anemia and increased in iron overload and hemochromatosis. § Ferritin is often increased in several other conditions, such as chronic infections, malignancy, and viral hepatitis.

Abnormal results § In iron deficiency, the iron level is low but the TIBC is increased, thus transferrin saturation becomes very low. § In iron overload states, such as hemochromatosis, the iron level will be high and the TIBC will be low or normal, causing the transferrin saturation to increase.

Test Preparation § Fasting is required for a TIBC test to ensure the most accurate results. This means the patient shouldn’t eat or drink anything for at least 8 hours before the test. § Certain medicines also may affect the result. § These medicines include: 1. Adrenocorticotropic hormone (ACTH) 2. Birth control pills 3. Chloramphenicol 4. Fluorides § Only the doctor will tell if someone need to stop taking any of these medicines or others.

Why the test in performed ? § Doctors typically order TIBC tests to check for medical conditions that cause abnormal iron levels. § A TIBC test may be ordered along with a serum iron test, which measures the amount of iron in your blood. Together, these tests help to evaluate people suspected of having either iron deficiency or iron overload.

§ It is customary to test for transferrin (instead of TIBC) when evaluating a person's nutritional status or liver function. § Because it is made in the liver, transferrin will be low in those with liver disease. § Transferrin levels also drop when there is not enough protein in the diet, so this test can be used to monitor nutrition.

Common causes of high iron levels § § § (low TIBC or Transferrin) Hemolytic anemia Iron or lead poisoning Frequent blood transfusions Liver damage In rare cases, high iron levels may be caused by an overdose of vitamins or iron supplements.

Common causes of high TIBC § A high TIBC or transferrin usually indicates iron deficiency § But they are also increased in pregnancy and with the use of oral contraceptives.

Questions : 1. What are your impression about serum iron picture ? 2. In your oponion; What is the possible diagnosis of her status ? 3. Explain the possible causes of your judgment ?