Zinc Protoporphyrin

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Pamela J Kling - One of the best experts on this subject based on the ideXlab platform.

Sharon E Blohowiak - One of the best experts on this subject based on the ideXlab platform.

Robert F Labbe - One of the best experts on this subject based on the ideXlab platform.

  • iron assessment tests transferrin receptor vis a vis Zinc Protoporphyrin
    Clinical Biochemistry, 2004
    Co-Authors: Robert F Labbe, Anjana Dewanji
    Abstract:

    Objectives: To review and compare the biochemical, analytical, and clinical features of two relatively new tests for assessing iron status and diagnosing iron disorders, namely, the serum transferrin receptor concentration (sTfR) and the erythrocyte Zinc Protoporphyrin/heme ratio (ZnPP/H). To consider the merits of each test for the diagnosis of iron disorders with emphasis on iron-deficient erythropoiesis, especially in the clinically important preanemia stage of iron depletion. Conclusions: Although the basic biochemical mechanisms underlying the two tests are very different, both of these tests are noteworthy because they are considered to reflect iron status in the bone marrow. The principal advantage to serum transferrin receptor is the lack of a response to anemia of chronic disease (ACD), which affects other iron status indicators, for example, ferritin and transferrin saturation. The principal advantage to erythrocyte Zinc Protoporphyrin is low cost, but point-of-care testing and simplicity can also be advantages. Both serum transferrin receptor and erythrocyte Zinc Protoporphyrin have been demonstrated to be useful in a variety of clinical situations. Serum transferrin receptor can be best used in diagnosing iron disorders, especially for patients with pathologies that may affect iron metabolism. Erythrocyte Zinc Protoporphyrin can be best used as a primary screening test for assessing iron status, especially in patients likely to have uncomplicated iron deficiency. While these applications are primary, both tests are more broadly useful, for example, in monitoring iron therapy.

  • Zinc Protoporphyrin a metabolite with a mission
    Clinical Chemistry, 1999
    Co-Authors: Robert F Labbe, Hendrik J. Vreman, David K. Stevenson
    Abstract:

    Zinc Protoporphyrin (ZnPP) is a normal metabolite that is formed in trace amounts during heme biosynthesis. The final reaction in the biosynthetic pathway of heme is the chelation of iron with Protoporphyrin. During periods of iron insufficiency or impaired iron utilization, Zinc becomes an alternative metal substrate for ferrochelatase, leading to increased ZnPP formation. Evidence suggests that this metal substitution is one of the first biochemical responses to iron depletion, causing increased ZnPP to appear in circulating erythrocytes. Because this Zinc-for-iron substitution occurs predominantly within the bone marrow, the ZnPP/heme ratio in erythrocytes reflects iron status in the bone marrow. In addition, ZnPP may regulate heme catabolism through competitive inhibition of heme oxygenase, the rate-limiting enzyme in the heme degradation pathway that produces bilirubin and carbon monoxide. Physiological roles, especially relating to carbon monoxide and possibly nitric oxide production, have been suggested for ZnPP. Clinically, ZnPP quantification is valuable as a sensitive and specific tool for evaluating iron nutrition and metabolism. Diagnostic determinations are applicable in a variety of clinical settings, including pediatrics, obstetrics, and blood banking. ZnPP analytical methodologies for clinical studies are discussed. In addition to diagnostic tests and metabolic studies, ZnPP has a potential therapeutic application in controlling bilirubin formation in neonates as a preventive measure for hyperbilirubinemia. Biochemical research techniques, both in vivo and in vitro, are described for further studies into the role of ZnPP in metabolism and physiology.

  • observations on the Zinc Protoporphyrin heme ratio in whole blood
    Clinical Chemistry, 1999
    Co-Authors: Robert F Labbe, Anjana Dewanji, Kathleen Mclaughlin
    Abstract:

    Zinc Protoporphyrin (ZPP) is a normal metabolite that accumulates at trace amounts in erythrocytes during hemoglobin synthesis. In states of inadequate iron delivery to developing red cells, excess ZPP forms as a by-product of the heme biosynthetic pathway. This ZPP response occurs because iron and Zinc interact as ferrochelatase substrates, with Zinc utilization increasing when the iron supply is diminished (1). The resulting high Zinc Protoporphyrin/heme ratio (ZPP/H) in circulating erythrocytes reflects a state of relative iron-deficient erythropoiesis (2). Either the whole blood or erythrocyte ZPP/H ratio in μmol/mol can be determined conveniently using hematofluorometry (3), a technique for front-surface fluorescence/absorption measurement (4). Despite its ease of determination and its clinical utility (5), ZPP/H has found only limited application in patient care. Criticism of ZPP/H determination has been based largely on interference from plasma components, primarily bilirubin (6)(7)(8). Other less common analytical pitfalls that have been cited include incomplete hemoglobin oxygenation (9) and the degree of hemolysis (10). Accordingly, we undertook an evaluation of the analytical procedure to try to understand and alleviate these factors associated with hematofluorometry. When the ZPP/H ratio is determined as prescribed, we believe that clinically acceptable analytical quality can be maintained. Furthermore, the highly sensitive, cost-effective ZPP/H ratio has merit as a primary test for assessing iron status and for monitoring iron therapy. For this evaluation, we used anticoagulated whole blood specimens obtained from our clinical hematology laboratories after all ordered tests had been completed. The blood had been collected in Vacutainer 3.0-mL Hemogard Tubes containing 3.0 mg EDTA (K3). Approval was obtained from the Human Subjects Division, Office of Research …

  • Observations on the Zinc Protoporphyrin/Heme Ratio in Whole Blood
    Clinical chemistry, 1999
    Co-Authors: Robert F Labbe, Anjana Dewanji, Kathleen Mclaughlin
    Abstract:

    Zinc Protoporphyrin (ZPP) is a normal metabolite that accumulates at trace amounts in erythrocytes during hemoglobin synthesis. In states of inadequate iron delivery to developing red cells, excess ZPP forms as a by-product of the heme biosynthetic pathway. This ZPP response occurs because iron and Zinc interact as ferrochelatase substrates, with Zinc utilization increasing when the iron supply is diminished (1). The resulting high Zinc Protoporphyrin/heme ratio (ZPP/H) in circulating erythrocytes reflects a state of relative iron-deficient erythropoiesis (2). Either the whole blood or erythrocyte ZPP/H ratio in μmol/mol can be determined conveniently using hematofluorometry (3), a technique for front-surface fluorescence/absorption measurement (4). Despite its ease of determination and its clinical utility (5), ZPP/H has found only limited application in patient care. Criticism of ZPP/H determination has been based largely on interference from plasma components, primarily bilirubin (6)(7)(8). Other less common analytical pitfalls that have been cited include incomplete hemoglobin oxygenation (9) and the degree of hemolysis (10). Accordingly, we undertook an evaluation of the analytical procedure to try to understand and alleviate these factors associated with hematofluorometry. When the ZPP/H ratio is determined as prescribed, we believe that clinically acceptable analytical quality can be maintained. Furthermore, the highly sensitive, cost-effective ZPP/H ratio has merit as a primary test for assessing iron status and for monitoring iron therapy. For this evaluation, we used anticoagulated whole blood specimens obtained from our clinical hematology laboratories after all ordered tests had been completed. The blood had been collected in Vacutainer 3.0-mL Hemogard Tubes containing 3.0 mg EDTA (K3). Approval was obtained from the Human Subjects Division, Office of Research …

Anjana Dewanji - One of the best experts on this subject based on the ideXlab platform.

  • iron assessment tests transferrin receptor vis a vis Zinc Protoporphyrin
    Clinical Biochemistry, 2004
    Co-Authors: Robert F Labbe, Anjana Dewanji
    Abstract:

    Objectives: To review and compare the biochemical, analytical, and clinical features of two relatively new tests for assessing iron status and diagnosing iron disorders, namely, the serum transferrin receptor concentration (sTfR) and the erythrocyte Zinc Protoporphyrin/heme ratio (ZnPP/H). To consider the merits of each test for the diagnosis of iron disorders with emphasis on iron-deficient erythropoiesis, especially in the clinically important preanemia stage of iron depletion. Conclusions: Although the basic biochemical mechanisms underlying the two tests are very different, both of these tests are noteworthy because they are considered to reflect iron status in the bone marrow. The principal advantage to serum transferrin receptor is the lack of a response to anemia of chronic disease (ACD), which affects other iron status indicators, for example, ferritin and transferrin saturation. The principal advantage to erythrocyte Zinc Protoporphyrin is low cost, but point-of-care testing and simplicity can also be advantages. Both serum transferrin receptor and erythrocyte Zinc Protoporphyrin have been demonstrated to be useful in a variety of clinical situations. Serum transferrin receptor can be best used in diagnosing iron disorders, especially for patients with pathologies that may affect iron metabolism. Erythrocyte Zinc Protoporphyrin can be best used as a primary screening test for assessing iron status, especially in patients likely to have uncomplicated iron deficiency. While these applications are primary, both tests are more broadly useful, for example, in monitoring iron therapy.

  • observations on the Zinc Protoporphyrin heme ratio in whole blood
    Clinical Chemistry, 1999
    Co-Authors: Robert F Labbe, Anjana Dewanji, Kathleen Mclaughlin
    Abstract:

    Zinc Protoporphyrin (ZPP) is a normal metabolite that accumulates at trace amounts in erythrocytes during hemoglobin synthesis. In states of inadequate iron delivery to developing red cells, excess ZPP forms as a by-product of the heme biosynthetic pathway. This ZPP response occurs because iron and Zinc interact as ferrochelatase substrates, with Zinc utilization increasing when the iron supply is diminished (1). The resulting high Zinc Protoporphyrin/heme ratio (ZPP/H) in circulating erythrocytes reflects a state of relative iron-deficient erythropoiesis (2). Either the whole blood or erythrocyte ZPP/H ratio in μmol/mol can be determined conveniently using hematofluorometry (3), a technique for front-surface fluorescence/absorption measurement (4). Despite its ease of determination and its clinical utility (5), ZPP/H has found only limited application in patient care. Criticism of ZPP/H determination has been based largely on interference from plasma components, primarily bilirubin (6)(7)(8). Other less common analytical pitfalls that have been cited include incomplete hemoglobin oxygenation (9) and the degree of hemolysis (10). Accordingly, we undertook an evaluation of the analytical procedure to try to understand and alleviate these factors associated with hematofluorometry. When the ZPP/H ratio is determined as prescribed, we believe that clinically acceptable analytical quality can be maintained. Furthermore, the highly sensitive, cost-effective ZPP/H ratio has merit as a primary test for assessing iron status and for monitoring iron therapy. For this evaluation, we used anticoagulated whole blood specimens obtained from our clinical hematology laboratories after all ordered tests had been completed. The blood had been collected in Vacutainer 3.0-mL Hemogard Tubes containing 3.0 mg EDTA (K3). Approval was obtained from the Human Subjects Division, Office of Research …

  • Observations on the Zinc Protoporphyrin/Heme Ratio in Whole Blood
    Clinical chemistry, 1999
    Co-Authors: Robert F Labbe, Anjana Dewanji, Kathleen Mclaughlin
    Abstract:

    Zinc Protoporphyrin (ZPP) is a normal metabolite that accumulates at trace amounts in erythrocytes during hemoglobin synthesis. In states of inadequate iron delivery to developing red cells, excess ZPP forms as a by-product of the heme biosynthetic pathway. This ZPP response occurs because iron and Zinc interact as ferrochelatase substrates, with Zinc utilization increasing when the iron supply is diminished (1). The resulting high Zinc Protoporphyrin/heme ratio (ZPP/H) in circulating erythrocytes reflects a state of relative iron-deficient erythropoiesis (2). Either the whole blood or erythrocyte ZPP/H ratio in μmol/mol can be determined conveniently using hematofluorometry (3), a technique for front-surface fluorescence/absorption measurement (4). Despite its ease of determination and its clinical utility (5), ZPP/H has found only limited application in patient care. Criticism of ZPP/H determination has been based largely on interference from plasma components, primarily bilirubin (6)(7)(8). Other less common analytical pitfalls that have been cited include incomplete hemoglobin oxygenation (9) and the degree of hemolysis (10). Accordingly, we undertook an evaluation of the analytical procedure to try to understand and alleviate these factors associated with hematofluorometry. When the ZPP/H ratio is determined as prescribed, we believe that clinically acceptable analytical quality can be maintained. Furthermore, the highly sensitive, cost-effective ZPP/H ratio has merit as a primary test for assessing iron status and for monitoring iron therapy. For this evaluation, we used anticoagulated whole blood specimens obtained from our clinical hematology laboratories after all ordered tests had been completed. The blood had been collected in Vacutainer 3.0-mL Hemogard Tubes containing 3.0 mg EDTA (K3). Approval was obtained from the Human Subjects Division, Office of Research …

R J Cooke - One of the best experts on this subject based on the ideXlab platform.

  • Zinc Protoporphyrin/haem ratio and plasma ferritin in preterm infants
    Archives of disease in childhood. Fetal and neonatal edition, 2002
    Co-Authors: Ian J. Griffin, M M Reid, Kpb Mccormick, R J Cooke
    Abstract:

    Objective: To study the utility of the Zinc Protoporphyrin/haem (ZPP/H) ratio as a measure of iron status in healthy, growing, preterm infants. Method: ZPP/H was measured in 109 well, preterm infants from the time of hospital discharge until 1 year of age (637 determinations). Results: ZPP/H was initially high, but steadily declined. This was opposite to what was expected from the known changes in iron stores during the first year of life and the observed changes in plasma ferritin. Subjects with higher ZPP/H ratios tended to have lower ferritins, but changes in ZPP/H in a given subject were poorly reflected by changes in plasma ferritin. Between 6 and 9 months of age, ZPP/H correlated with other measures of iron status, but serum ferritin concentration did not. Conclusion: Use of the ZPP/H ratio as a measure of iron status during the first year of life appears to be confounded by the developmental changes in ZPP/H, but in the later half of this period it may be a better measure of iron status than serum ferritin.

  • Zinc Protoporphyrin haem ratio and plasma ferritin in preterm infants
    Archives of Disease in Childhood-fetal and Neonatal Edition, 2002
    Co-Authors: Ian J. Griffin, M M Reid, Kenny Mccormick, R J Cooke
    Abstract:

    Objective: To study the utility of the Zinc Protoporphyrin/haem (ZPP/H) ratio as a measure of iron status in healthy, growing, preterm infants. Method: ZPP/H was measured in 109 well, preterm infants from the time of hospital discharge until 1 year of age (637 determinations). Results: ZPP/H was initially high, but steadily declined. This was opposite to what was expected from the known changes in iron stores during the first year of life and the observed changes in plasma ferritin. Subjects with higher ZPP/H ratios tended to have lower ferritins, but changes in ZPP/H in a given subject were poorly reflected by changes in plasma ferritin. Between 6 and 9 months of age, ZPP/H correlated with other measures of iron status, but serum ferritin concentration did not. Conclusion: Use of the ZPP/H ratio as a measure of iron status during the first year of life appears to be confounded by the developmental changes in ZPP/H, but in the later half of this period it may be a better measure of iron status than serum ferritin.

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