hemoglobin S

hemoglobin /he·mo·glo·bin/ (he´mo-glo″bin) the oxygen-carrying pigment of erythrocytes, formed by developing erythrocytes in the bone marrow; a hemoprotein made up of four different polypeptide globin chains that contain between 141 and 146 amino acids. Hemoglobin A is normal adult hemoglobin and hemoglobin F is fetal hemoglobin. Many abnormal hemoglobins have been reported; the first were given capital letters such as hemoglobin E, H, M, and S, and later ones have been named for the place of discovery. Homozygosity for hemoglobin S results in sickle cell anemia, heterozygosity in sickle cell trait. Symbol Hb.

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fetal hemoglobin  that forming more than half of the hemoglobin of the fetus, present in minimal amounts in adults and abnormally elevated in certain blood disorders.

mean corpuscular hemoglobin  (MCH) the average hemoglobin content of an erythrocyte.

muscle hemoglobin  myoglobin.

reduced hemoglobin  that not combined with oxygen.

hemoglobin S  the most common abnormal hemoglobin, with valine substituted for glutamic acid at position six of the beta chain, resulting in the abnormal erythrocytes called sickle cells, and causing sickle cell anemia.

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hemoglobin S

n. Abbr. Hb S

An abnormal hemoglobin in which valine has replaced glutamic acid causing the hemoglobin to become less soluble under decreasing oxygen concentrations and to polymerize into crystals that distort the red blood cells into a sickle shape. Also called sickle cell hemoglobin.

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Hemoglobin S

Hemoglobin produced in association with the sickle cell trait; the beta-globin molecules of hemoglobin S are defective.

Mentioned in: Sickle Cell Disease

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hemoglobin S (Hb S),

an abnormal type of hemoglobin, characterized by the substitution of the amino acid valine for glutamic acid in the beta chain of the hemoglobin molecule. These molecules move more slowly and are much less soluble than hemoglobin A. As the abnormal molecules become deoxygenated, because of decreased oxygen tension in the peripheral circulation, they become sickle-shaped, move slowly, clump together, and hemolyze. If the proportion of Hb S to Hb A is large, as in sickle cell anemia, local thrombosis and infarction may occur. See also sickle cell anemia, sickle cell crisis, sickle cell trait.

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Patient discussion about hemoglobin S.

Q. What is the Definition of Anemia? My doctor told me I have anemia, based on my latest blood tests. What is anemia?

A. Anemia is defined as a deficiency of hemoglobin, a molecule inside the red blood cells (RBC's). The hemoglobin is responsible for carrying the oxygen that we breath from the lungs to the body tissues. Anemia causes lack of oxygen in the organs, in different degrees. A regular blood test can discover anemia, simply if the hemoglobin (Hb) level is lower than 13.0 g/dL in adult men and lower than 12.0 g/dL in adult women. The blood test can also suggest on the cause of the anemia, depending on other values that can be measured.

Q. Can Jantoven cause hemoglobin to drop?

A. Yes. In that case, you may consider consulting a doctor, since it may result from bleeding that may necessitate treatment.