A hemoglobin test measures the amount of hemoglobin in your blood.
Guide. A glycohemoglobin test, or hemoglobin A1c, is a blood test that checks the amount of sugar (glucose) bound to the hemoglobin in the red blood cells. When hemoglobin and glucose bond, a coat of sugar forms on the hemoglobin. Glucose binds to hemoglobin in red blood cells at a steady rate. Since red blood cells last 3 to 4 months, the A1c test shows how much glucose is in the plasma part of blood. HbA 1c is a measure of the beta-N-1-deoxy fructosyl component of hemoglobin. Normal levels of glucose produce a normal amount of glycated hemoglobin. As the average amount of plasma glucose increases, the fraction of glycated hemoglobin increases in a predictable way. This serves as a marker for average blood glucose levels over the previous 3 months prior to the measurement as this is the half life of red blood cells. Glycated hemoglobin measurement is not appropriate where there has been a change in diet or treatment within 6 weeks. Likewise, the test assumes a normal red blood cell aging process and mix of hemoglobin subtypes (predominantly HbA in normal adults). Glycated hemoglobin (hemoglobin A1c, HbA1c, A1C, or Hb1c; sometimes also HbA1c or HGBA1C) is a form of hemoglobin that is measured primarily to identify the average plasma glucose concentration over prolonged periods of time. Glycated hemoglobin measurement is not appropriate where there has been a change in diet or treatment within 6 weeks. Likewise, the test assumes a normal red blood cell aging process and mix of hemoglobin subtypes (predominantly HbA in normal adults). The hemoglobin test is often used to check for anemia, usually along with a hematocrit or as part of a complete blood count (CBC) . The test may be used to screen for, diagnose, or monitor a number of conditions and diseases that affect red blood cells (RBCs) and/or the amount of hemoglobin in blood. 1 Screen for, diagnose, and measure the severity of anemia (low RBCs, hemoglobin and hematocrit) or polycythemia (high RBCs, hemoglobin and hematocrit). 2  Monitor the response to treatment of anemia or polycythemia. 3  Help make decisions about blood transfusions or other treatments if the anemia is severe. 1 To measure the hemoglobin concentration, a lysing agent is added to a sample of diluted blood; the lysing agent disrupts all the red blood cells in the sample and releases the hemoglobin into the fluid so that the sample then consists of a solution of hemoglobin.  Hemoglobin is the protein molecule in red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues back to the lungs. Hemoglobin is made up of four protein molecules (globulin chains) that are connected together. Each globulin chain contains an important central structure called the heme molecule. Embedded within the heme molecule is iron that is vital in transporting oxygen and carbon dioxide in our blood. The iron contained in hemoglobin is also responsible for the red color of blood. In the simplest terms, hemoglobin A1C (known asHbA1c or A1C) is measured in people with diabetesto provide an index of average blood glucose for theprevious three to four months. A1C is glucose attached to hemoglobin, a proteinfound in red blood cells that transports oxygen fromthe lungs to other parts of the body. Hemoglobin is composed of four globin (protein)chains; two beta (b) and two alpha (a) chains.Each chain has a heme attached, the site for thebinding of oxygen to hemoglobin. Definition. A hemoglobin test measures the amount of hemoglobin in your blood. Hemoglobin is a protein in your red blood cells that carries oxygen to your body's organs and tissues and transports carbon dioxide from your organs and tissues back to your lungs. If a hemoglobin test reveals that your hemoglobin level is lower than normal, it means you have a low red blood cell count (anemia). Anemia can have many different causes, including vitamin deficiencies, bleeding and chronic disease Hematocrit, the proportion of blood volume occupied by red blood cells, is typically about three times the hemoglobin concentration measured in g/dL. For example, if the hemoglobin is measured at 17 g/dL, that compares with a hematocrit of 51%. Hemoglobin is also found outside red blood cells and their progenitor lines. Other cells that contain hemoglobin include the A9 dopaminergic neurons in the substantia nigra, macrophages, alveolar cells, and mesangial cells in the kidney. Hemoglobin is usually measured as a part of the complete blood count (CBC) test from a blood sample. Several methods exist for measuring hemoglobin, most of which are done currently by automated machines designed to perform different tests on blood. Within the machine, the red blood cells are broken down to get the hemoglobin into a solution.
http://www.webmd.com/diabetes/glycohemoglobin-ghb https://en.wikipedia.org/wiki/Glycated_hemoglobin https://en.wikipedia.org/wiki/Glycated_hemoglobin https://labtestsonline.org/understanding/analytes/hemoglobin/tab/test http://www.eclinpath.com/hematology/tests/hemoglobin/ http://www.medicinenet.com/hemoglobin/article.htm https://www.diabeteshealth.com/what-is-a1c-and-what-does-it-measure/ http://www.mayoclinic.org/tests-procedures/hemoglobin-test/basics/definition/PRC-20015022 https://en.wikipedia.org/wiki/Hemoglobin http://www.medicinenet.com/hemoglobin/page2.htm
what is hemoglobin a measure of