Plasma iron and transferrin iron-binding capacity evaluated by colorimetric and immunoprecipitation methods.

Abstract We evaluated plasma iron (PI) and total iron-binding capacity (TIBC) or transferrin in normal individuals and in patients with iron imbalance. The standard colorimetric measurements of PI and TIBC and the standard isotope-dilution measurement of TIBC were compared with an immunoprecipitation method and also with immunoelectrophoresis of transferrin. PI concentrations as measured by the standard and immunoprecipitation methods agreed closely for all individuals except those with saturated transferrin, where nontransferrin iron increased the results in the standard assay. This excess iron in saturated plasma may be derived from either free iron or iron-bearing ferritin. There were also differences in TIBC between the two methods. Iron-deficient sera gave higher values for transferrin when measured by immunoelectrophoresis. Unsaturated iron-binding capacity was increased in the isotope-dilution method in some iron-saturated plasma, compounding errors when added to erroneously high PI values to compute TIBC. Perhaps some exchange of iron occurred between added iron and transferrin iron in the isotope-dilution method. These measurements confirm the accuracy of the standard colorimetric method of measuring PI and TIBC except in iron-saturated plasma. However, the greater specificity of a polyclonal immunoprecipitation method of measuring PI and TIBC makes it particularly useful in differentiating transferrin-bound iron from nontransferrin iron.

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Effect of transfused reticulocytes on iron exchange

Blood ◽

10.1182/blood.v59.2.364.bloodjournal592364 ◽

1982 ◽

Vol 59 (2) ◽

pp. 364-369

Author(s):

CA Finch ◽

H Huebers ◽

M Eng ◽

L Miller

Keyword(s):

Exchange Transfusion ◽

Iron Absorption ◽

Binding Capacity ◽

Transferrin Saturation ◽

Iron Binding ◽

Plasma Iron ◽

Iron Deficient ◽

Before And After ◽

Iron Binding Capacity ◽

Iron Exchange

A animal model was developed whereby reticulocyte-rich blood was introduced into normal rats by exchange transfusion. Measurements of plasma iron turnover was made at similar plasma iron concentrations before and after exchange transfusions. High reticulocyte blood obtained from animals rendered iron deficient by diet or by treatment with phenylhydrazine resulted in a mean increase of 86% in internal iron exchange, while the plasma iron turnover was unaffected by exchange with normal red cells. Since iron input from reticuloendothelial cells could have increased due to breakdown of transfused cells, iron absorption was also measured. Within 1 hr and for a least 6 hr after exchange with high reticulocyte blood, mean absorption in six groups of animals was increased over control animals by 50%-130%. The increased plasma iron turnover and absorption was not mediated by a decrease in plasma iron or an increase in unsaturated iron-binding capacity. Indeed, a higher plasma iron and transferrin saturation augmented the movement of iron into the plasma from iron- donating tissues. It is proposed that the donation of iron by transferrin in some way immediately facilitates the procurement of more iron by transferrin.

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Effect of transfused reticulocytes on iron exchange

Blood ◽

10.1182/blood.v59.2.364.364 ◽

1982 ◽

Vol 59 (2) ◽

pp. 364-369 ◽

Cited By ~ 42

Author(s):

CA Finch ◽

H Huebers ◽

M Eng ◽

L Miller

Keyword(s):

Exchange Transfusion ◽

Iron Absorption ◽

Binding Capacity ◽

Transferrin Saturation ◽

Iron Binding ◽

Plasma Iron ◽

Iron Deficient ◽

Before And After ◽

Iron Binding Capacity ◽

Iron Exchange

Abstract A animal model was developed whereby reticulocyte-rich blood was introduced into normal rats by exchange transfusion. Measurements of plasma iron turnover was made at similar plasma iron concentrations before and after exchange transfusions. High reticulocyte blood obtained from animals rendered iron deficient by diet or by treatment with phenylhydrazine resulted in a mean increase of 86% in internal iron exchange, while the plasma iron turnover was unaffected by exchange with normal red cells. Since iron input from reticuloendothelial cells could have increased due to breakdown of transfused cells, iron absorption was also measured. Within 1 hr and for a least 6 hr after exchange with high reticulocyte blood, mean absorption in six groups of animals was increased over control animals by 50%-130%. The increased plasma iron turnover and absorption was not mediated by a decrease in plasma iron or an increase in unsaturated iron-binding capacity. Indeed, a higher plasma iron and transferrin saturation augmented the movement of iron into the plasma from iron- donating tissues. It is proposed that the donation of iron by transferrin in some way immediately facilitates the procurement of more iron by transferrin.

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PLASMA IRON AND IRON-BINDING CAPACITY

The Lancet ◽

10.1016/s0140-6736(75)92573-8 ◽

1975 ◽

Vol 305 (7919) ◽

pp. 1293

Author(s):

Terry Hamblin

Keyword(s):

Binding Capacity ◽

Iron Binding ◽

Plasma Iron ◽

Iron Binding Capacity

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Iron preparations for children

Drug and Therapeutics Bulletin ◽

10.1136/dtb.4.3.9 ◽

1966 ◽

Vol 4 (3) ◽

pp. 9-11

Keyword(s):

Bone Marrow ◽

Iron Deficiency ◽

Blood Smear ◽

Binding Capacity ◽

Iron Binding ◽

Iron Stores ◽

Plasma Iron ◽

Hypochromic Anaemia ◽

Iron Binding Capacity

We have discussed iron preparations for adults in earlier articles;1 much of the information applies equally to children. Iron is not a ‘tonic’ and should be given only to prevent or correct iron deficiency. Estimation of the haemoglobin and inspection of a blood smear are the minimum investigations necessary before iron is prescribed in therapy. When deficiency is suspected in the absence of hypochromic anaemia, plasma iron and iron-binding capacity should be estimated and/or the bone marrow examined for haemosiderin crystals which disappear when iron stores are depleted.

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Ferrozine iron and total iron-binding capacity method adapted to the ABA-100 Bichromatic Analyzer.

Clinical Chemistry ◽

10.1093/clinchem/27.8.1441 ◽

1981 ◽

Vol 27 (8) ◽

pp. 1441-1444 ◽

Cited By ~ 4

Author(s):

L Mori ◽

A Bekkering ◽

J Traini ◽

L Vanderlinden

Keyword(s):

Binding Capacity ◽

Magnesium Carbonate ◽

Total Iron ◽

Iron Binding ◽

Total Iron Binding Capacity ◽

Standard Curve ◽

Excess Iron ◽

Color Reagent ◽

Iron Binding Capacity ◽

Capacity Method

Abstract A sensitive method (Clin. Chem. 26: 327--331, 1980) for serum iron, in which the color reagent Ferrozine is used, is modified and adapted to the Abbott ABA-100 discrete analyzer. The standard curve is linear to at least 10 mg/L and the method showed day-to-day precision (CV) of 2.4% for a 1.03 mg/L sample (n = 63) and 1.9% for a 2.13 mg/L sample (n = 63). Lower values were obtained than with the modified continuous-flow technique of Giovanniello et al., but the correlation was good (r = 0.98). Bilirubin and copper do not interfere; hemoglobin and gross lipemia interfere only slightly. The total iron-binding capacity, based on Ramsay's method, was evaluated with regard to the effect of adding various amounts of magnesium carbonate. Results led us to use a ratio of approximately 180 mg of magnesium carbonate to each 5 micrograms of excess iron added. Day-to-day, the method for total iron-binding capacity gave a CV of 3.1% for a 2.55 mg/L sample, 2.8% for a 3.63 mg/L sample.

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Serum iron and total iron-binding capacity compared with serum ferritin in assessment of iron deficiency.

Clinical Chemistry ◽

10.1093/clinchem/27.2.276 ◽

1981 ◽

Vol 27 (2) ◽

pp. 276-279 ◽

Cited By ~ 15

Author(s):

F Peter ◽

S Wang

Keyword(s):

Iron Deficiency ◽

Serum Ferritin ◽

Serum Iron ◽

Binding Capacity ◽

Transferrin Saturation ◽

Total Iron ◽

Iron Binding ◽

Total Iron Binding Capacity ◽

Iron Deficient ◽

Iron Binding Capacity

Abstract Ferritin values for 250 selected sera were compared with values for iron, total iron-binding capacity (TIBC), and transferrin saturation, to assess the potential of the ferritin assay for the detection of latent iron deficiency. The specimens were grouped (50 in each group) according to their values for iron and TIBC. In Group 1 (low iron, high TIBC) the saturation and ferritin values both indicated iron deficiency in all but one. In the 100 specimens of Groups 2 (normal iron, high TIBC) and 4 (normal iron, high normal TIBC), the saturation values revealed 16 iron-deficient cases, the ferritin test 55. For Groups 3 (low iron, normal TIBC) and 5 (low iron, low TIBC), the ferritin test revealed fewer cases of iron deficiency than did the saturation values (37 cases vs 51 cases, in the 100 specimens). Evidently the ferritin test detects iron deficiency in many cases for whom the serum iron and TIBC tests are not positively indicative. The correlation of serum ferritin with iron, TIBC, and transferrin saturation in the five groups was good only in the case of specimens for which the TIBC was normal; if it was abnormal the correlation was very poor.

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Use of an Anion-Exchange Column to Determine Serum Iron-Binding Capacity

Clinical Chemistry ◽

10.1093/clinchem/17.9.941 ◽

1971 ◽

Vol 17 (9) ◽

pp. 941-947 ◽

Cited By ~ 3

Author(s):

H Peter Lehmann ◽

Alex Kaplan

Keyword(s):

Serum Iron ◽

Binding Capacity ◽

Ferric Citrate ◽

Iron Binding ◽

Resin Column ◽

Anion Exchange Column ◽

Excess Iron ◽

Colorimetric Measurement ◽

Color Reagent ◽

Iron Binding Capacity

Abstract A rapid procedure is described for determining total iron-binding capacity (TIBC) by use of a small, disposable resin column. Serum is saturated with excess ferric citrate, and iron not bound to protein is then removed by passing the mixture through the column of anion-exchanger. Transferrin-bound iron in the effluent, the TIBC, is determined colorimetrically (AutoAnalyzer), with 2,4,6-tripyridyl-1,3,5-triazine as color reagent. The percentage saturation with iron may be obtained from colorimetric measurement of original serum iron and the TIBC, or by radioactive counting if 59Fe is incorporated in the ferric citrate used to saturate the serum. Our method is compared with the MgCO3 precipitation technique for the removal of excess iron after saturation and to an ultrafiltration technique in which protein-bound iron is retained by a membrane and the filtrate analyzed for unbound iron, thus obviating absorbents in the determination of TIBC. Results from the resin-column and ultrafiltration procedures correlated well, whereas those from the MgCO3 method were consistently lower and more erratic.

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