Total iron binding capacity

E583 Alexander N.M. and Jacobs, J.C. (1990). Colorimetric measurement of transferrin-bound serum iron, total iron-binding capacity, total iron, and iron-dextran. Clin. Chem. 36, 971, Abstr. 95. 

Iron Binding Capacity, Total (S) (TIBC) 250-450 /igldL 44.75-80.55 /(mol/L... 

The concentration of transferrin in plasma is approximately 300 mg/dL. This amount of transferrin can bind 300 pg of iron per deciliter, so that this represents the total iron-binding capacity of plasma. However,... 

Determinations of plasma Iron, total Iron-binding capacity (TIBC), and % transferrin saturation... 

Hematological Methods. Hematological analyses can Include the determination of the total hemoglobin concentration (In g%), the packed cell volume (PCV In %), the red blood cell count (In 10 /mm ) and reticulocytes count (In %), calculation of the red cell Indices, examination of a blood film, tests to demonstrate the presence of Inclusion bodies and of sickle cells, tests to evaluate the distribution of fetal hemoglobin (Hb-F) Inside the red cells, the red cell osmotic fragility, the concentration of serum Iron (SI), total Iron binding capacity (TIBC), and the survival time of the red cells. Details of all... 

Yeh, Y-Y., and Zee, P. Mlcromethod for Determining Total Iron-Binding Capacity by Flameless Atomic Absorption Spectrophotometry". Clin. Chem. (1974), 20, 360-364. 

Iron is, as part of several proteins, such as hemoglobin, essential for vertebrates. The element is not available as ion but mostly as the protein ligands transferrin (transport), lactoferrin (milk), and ferritin (storage), and cytochromes (electron transport) (Alexander 1994). Toxicity due to excessive iron absorption caused by genetic abnormalities exists. For the determination of serum Fe a spectrophoto-metric reference procedure exists. Urine Fe can be determined by graphite furnace (GF)-AAS, and tissue iron by GF-AAS and SS-AAS (Alexander 1994 Herber 1994a). Total Iron Binding Capacity is determined by fuUy saturated transferrin with Fe(III), but is nowadays mostly replaced by immunochemical determination of transferrin and ferritin. 

Decreased red blood cell (RBC) count, hemoglobin (Hgb) and hematocrit (Hct) iron metabolism may also be altered [iron level, total iron binding capacity (TIBC), serum ferritin level, and transferrin saturation (TSAT)]. Erythropoietin levels are not routinely monitored and are generally normal to low. Urine positive for albumin or protein. 

Total iron-binding capacity (TIBQ—quantifies the ironbinding capacity of transferrin and is increased in iron-deficiency anemia... 

FIGURE 63-3. The anemia evaluation process. MCV, mean corpuscular volume Pb, lead TIBC, total iron binding capacity ACD, anemia of chronic disease. 

SH Social history TIBC Total iron-binding capacity... 

F, female M, male MCH, mean corpuscular hemoglobin MCHC, mean corpuscular hemoglobin concentration MCV, mean corpuscular volume RBC, red blood cell RDW, red blood cell distribution TIBC, total iron-binding capacity. 

The earliest and most sensitive laboratory change for iron-deficiency anemia is decreased serum ferritin (storage iron), which should be interpreted in conjunction with decreased transferrin saturation and increased total iron-binding capacity (TIBC). Hb, hematocrit, and RBC indices usually remain normal until later stages of iron-deficiency anemia. 

More recent determinations of serum iron have been reported by Schmidt 57), who simply diluted with lanthanum chloride solution, and by Tavenier and Hellen-doorn58), who deproteinized samples in the latter study, iron in the protein precipitate is analyzed to correct the serum iron level. Uny etal. 59) determined serum iron, using ultrasonic nebulization of the sample to increase the sensitivity. Olson and Hamlin 6°) have determined serum iron and total iron-binding capacity. Proteins are precipitated and iron (III) is released by heating with trichloroacetic acid. 

Iron (and/or other related parameters such as ferritin, total iron binding capacity)... 

For patients who are treated chronically with parenteral iron, it is important to monitor iron storage levels to avoid the serious toxicity associated with iron overload. Unlike oral iron therapy, which is subject to the regulatory mechanism provided by the intestinal uptake system, parenteral administration, which bypasses this regulatory system, can deliver more iron than can be safely stored. Iron stores can be estimated on the basis of serum concentrations of ferritin and the transferrin saturation, which is the ratio of the total serum iron concentration to the total iron-binding capacity ( ). 

There is an increase in serum iron and total iron-binding capacity similar to that reported in patients with hepatitis. 

Serum Total Iron and Total Iron Binding Capacity The results for the determination of serum total iron and total iron-binding capacity of rats fed treatment diets for 18 months are also listed in Table VI. A significant increase in serum total iron was detected in rats fed the Maillard browned egg albumin over their control group. Increased serum total iron with normal total iron binding capacity is associated with hemolytic anemia, hemochromatosis, hemosiderosis, and hepatitis (30 ). On the basis of other clinical and histopathological data, however, none of these causes are likely. 

Know the function and diagnostic utility of transferrin and ferritin and be able to solve problems involving total iron and total iron binding capacity. 

Under normal circumstances, transferrin is one-fourth to one-third saturated with iron. The level of saturation may decrease in systemic infection or cancer and in iron deficiency anemia, the most common nutritional deficiency in the United States. In individuals with iron deficiency anemia, transferrin levels are increased. The level of saturation with iron increases in iron overload syndromes such as hereditary hemochromatosis or as a result of repeated blood transfusions, as is the case in thalassemia patients. Determinations of total plasma iron (TI) and plasma total iron binding capacity (TIBC) are routinely performed in the clinical biochemistry laboratory. The TIBC value reflects transferrin levels in plasma the amount of iron that can be bound by transferrin is equal to TIBC x 0.7. Total plasma iron levels in iron deficiency anemia become abnormal before hemoglobin levels show any change. 

Serum total iron-binding capacity (p,/dL) 350 475b 263c... 

On further testing, the patient displayed the biochemical signs of iron overload. He had a serum iron of 197 mg/dL (reference 30-360 pg/dL), a total iron binding capacity of 202 pg/dL (reference 228-428 pg/dL), and a ferritin level of 4890 ng/mL (reference 30-300 ng/mL). His serum transferrin saturation was calculated to be 97.5% (reference 20%-50%). 

The diagnosis of HH is established based on serum transferrin saturation (TS), defined as serum iron divided by total iron binding capacity (TIBC). Since serum iron and ferritin levels lack specificity for diagnosis when used alone, measurement of fasting TS is currendy recommended as a first screen to detect iron overload. TS is the best indirect biochemical marker of iron stores. A fasting TS of greater than 45% will detect over 98% of all cases of phenotypic hemochromatosis (Tavill, 2001). 

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