MLS 031 - Iron Kinetics and Laboratory Assessment PDF

Rodak's 6th Ed., Ch. 8, pg. 104 Laboratory Assessment Iron Kinetics and Prepared by: Hazel B. Velasco, RMT, D...

Rodak's 6th Ed., Ch. 8, pg. 104 Laboratory Assessment Iron Kinetics and Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), 07/13/2023 1 MLS(ASCPi)cm  07/13/2023 Iron Largest percentage (70%) of body iron is within hemoglobin in red blood cells. 20% - stored within hepatocytes and macrophages in the spleen and BM 10% - divided among the muscles, the cytochromes, various, iron-containing enzymes, and the plasma. Distributed in three (3) compartments: a. Functional compartment Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), – Iron functioning within cells such as iron (hemoglobin). Myoglobin (in muscles), and cytochromes (all cells other than mature RBCs). b. Storage compartment – Iron that is not currently functioning but is available when needed. Ex: Iron stored in macrophages and hepatocytes. c. Transport compartment - Iron that is in transit from one body site to another. MLS(ASCPi)cm 2  Iron Kinetics Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), 07/13/2023 3 MLS(ASCPi)cm  Absorption of Iron in the Intestines Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), 07/13/2023 4 MLS(ASCPi)cm  Iron Transport in the Blood Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), 07/13/2023 5 MLS(ASCPi)cm  Regulation of Body Iron Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), 07/13/2023 6 MLS(ASCPi)cm  Dietary Iron, 07/13/2023 Iron Recycling Bioavailability, and Largest percentage of recycled iron comes from Demand red blood cells. Senescent (aging) red blood cells are ingested by macrophages in the spleen. Foods containing high levels of iron Macrophages also possess ferroportin, which include red meats, legumes, and dark green leafy vegetables. Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), enables them to export iron. Exported iron is bound to apotransferrin. Iron can be absorbed as either ionic iron or nonionic iron. Haptoglobin – binds to hemoglobin; mediated by Only 1 to 2 mg is absorbed in US diet and macrophages with haptoglobin-hemoglobin is adequate for most men, but receptor menstruating women, pregnant and Hemopexin – binds to heme; mediated by lactating women, and growing children hepatocytes with hemopexin-heme receptor and usually need additional iron ferroportin (could transport iron to other body supplementation to meet their increased MLS(ASCPi)cm cells. need for iron. *Both are proteins, thus are unable to pass through the glomerulus, so the bound heme iron is retained in the body. 7  Laboratory Iron Status Assessment of Body Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), 07/13/2023 8 MLS(ASCPi)cm  Laboratory Assessment of Body Iron Status Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), 07/13/2023 9 MLS(ASCPi)cm Laboratory Test Use Comments/Notes: 07/13/2023 Serum Iron Indicator of available transport Advised to collect a fasting iron specimen early in the morning where levels are expected to be highest. Total Iron-Binding Capacity Indirect indicator of transferrin The amount of iron detected level represents all the binding sites available on transferrin, that is, Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), the total iron-binding capacity (TIBC). Percent Transferrin Saturation Indirect indicator of transport Calculated as: iron and transferrin level 𝑆𝑒𝑟𝑢𝑚 𝐼𝑟𝑜𝑛 x 100% = % Transferrin 𝑇𝐼𝐵𝐶 saturation Prussian Blue Staining Visual qualitative assessment of Prussian blue stain is considered tissue iron stores the gold standard for assessment MLS(ASCPi)cm of body iron stores. Zinc Protoporphyrin Indicator of functional iron Accumulates in red blood cells available in red blood cells when iron is not incorporated *Greatest when there is an into heme and zinc binds instead impaired ferrochelatase, such as in lead poisoning. to protoporphyrin IX. 10  07/13/2023 Laboratory Test Use Comments/Notes: Ferritin Indicator of iron stores The level of serum ferritin has been found to correlate highly with stored iron as assessed by Prussian blue stains of bone marrow. *The only drawback is that, Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), Ferritin is an acute-phase reactant, which may be falsely increased during an infection/inflammation (attempts to horde all iron away from bacteria ) Soluble transferrin receptor Indicator of functional iron Iron level is indirectly available in cells proportional to the number of MLS(ASCPi)cm TfR1 seen on the membrane. Hemoglobin Content of Indicator of functional iron The hemoglobin content of Reticulocytes available in developing red reticulocytes will drop when blood cells iron for erythropoiesis is restricted. 11  Thomas Plot Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), 07/13/2023 MLS(ASCPi)cm 12  07/13/2023 Reading Assignment: Prepared by: Hazel B. Velasco, RMT, DTA, MPH(inp.), Leukocyte Development, Kinetics, and Function. Rodak's 6th Ed., Ch. 9, pg. 117 MLS(ASCPi)cm 13