he·​mo·​glo·​bin | \ ˈhē-mə-ˌglō-bən How to pronounce hemoglobin (audio) \

Definition of hemoglobin

1 : an iron-containing respiratory pigment of vertebrate red blood cells that consists of a globin composed of four subunits each of which is linked to a heme molecule, that functions in oxygen transport to the tissues after conversion to oxygenated form in the gills or lungs, and that assists in carbon dioxide transport back to the gills or lungs after surrender of its oxygen
2 : any of numerous iron-containing respiratory pigments of various organisms (such as invertebrates and yeasts)

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Did You Know?

When filled with oxygen, the hemoglobin in your blood is bright red; returning to the lungs without its oxygen, it loses its brightness and becomes somewhat bluish. Hemoglobin levels can change from day to day, and may be affected by such factors as a lack of iron in the diet, a recent loss of blood, and being pregnant. When you give blood, a nurse first pricks your finger to test your hemoglobin level; a low hemoglobin count indicates anemia and may mean that you shouldn't give blood that day. Mild anemia is generally of little importance, but some types can be very serious.

Examples of hemoglobin in a Sentence

Recent Examples on the Web For instance, treating sickle cell requires that a mere 10% of red blood cells have healthy hemoglobin, which seems well within the reach of classic CRISPR. Sharon Begley, STAT, "New CRISPR tool has the potential to correct almost all disease-causing DNA glitches, scientists report," 21 Oct. 2019 Warren added that medication is able to return the missing electron to the hemoglobin molecule —the part of your blood which is in charge of oxygen levels — allowing oxygen to be correctly released into the tissue. Georgia Slater, PEOPLE.com, "Woman Suffers 'Rare Case' After Her Blood Turned Blue from Using Common Numbing Agent," 20 Sep. 2019 Many questions remain, though, including the most basic: How do Tibetans get enough oxygen without elevated levels of hemoglobin? Bridget Alex, Discover Magazine, "The World Is Our Niche," 3 June 2019 The gene therapy treats a condition, called beta thalassemia, caused by a gene mutation that hinders production of the hemoglobin molecules that carry oxygen through the blood. Jonathan D. Rockoff, WSJ, "New Gene Therapy Priced at $1.8 Million in Europe," 14 June 2019 That means my body also doesn’t always have enough hemoglobin, which is pretty key for survival. Joelle Zarcone, SELF, "My Cooley’s Anemia Helps Me View Workouts as a Gift, Not a Chore," 12 July 2019 The body adapts by making lots of extra red blood cells, which ferry oxygen attached to hemoglobin to organs and tissues. Xing Liu, Science Magazine, "At 5100 meters elevation, a Peruvian gold mining town is the world’s highest settlement—and a good place to study how life at extremely low oxygen levels ravages the body.," 12 Sep. 2019 Scientists are already well aware of the most abundant genes and proteins (think, for instance, of hemoglobin, which fills our blood and allows us to breathe). Eugene Koonin, Quartz, "What will we do once we’ve sequenced all the genomes?," 9 Aug. 2019 Four of the sickle cell patients have been followed for longer than three months and are now producing anti-sickling hemoglobin ranging from 32 percent to 62 percent. Adam Feuerstein, STAT, "New Bluebird data show promising benefits for gene therapy, if they last," 15 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'hemoglobin.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of hemoglobin

1869, in the meaning defined at sense 1

History and Etymology for hemoglobin

International Scientific Vocabulary, short for earlier hematoglobulin

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Statistics for hemoglobin

Last Updated

13 Nov 2019

Time Traveler for hemoglobin

The first known use of hemoglobin was in 1869

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More Definitions for hemoglobin


How to pronounce hemoglobin (audio)

English Language Learners Definition of hemoglobin

technical : the part of blood that contains iron, carries oxygen through the body, and gives blood its red color


he·​mo·​glo·​bin | \ ˈhē-mə-ˌglō-bən How to pronounce hemoglobin (audio) \

Kids Definition of hemoglobin

: a protein of red blood cells that contains iron and carries oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs


variants: or chiefly British haemoglobin \ ˈhē-​mə-​ˌglō-​bən How to pronounce haemoglobin (audio) \

Medical Definition of hemoglobin

1 : an iron-containing respiratory pigment of vertebrate red blood cells that functions primarily in the transport of oxygen from the lungs to the tissues of the body, that consists of four polypeptide chains of which two are of the type designated alpha and two are of one of the types designated beta, gamma, or delta and each of which is linked to a heme molecule, that combines loosely and reversibly with oxygen in the lungs or gills to form oxyhemoglobin and with carbon dioxide in the tissues to form carbaminohemoglobin, that in humans is present normally in blood to the extent of 14 to 16 grams in 100 milliliters expressed sometimes on a scale of 0 to 100 with an average normal value (as 15 grams) taken as 100, and that is determined in blood either colorimetrically or by quantitative estimation of the iron present — see fetal hemoglobin, hemoglobin a — compare carboxyhemoglobin, methemoglobin
2 : any of numerous iron-containing respiratory pigments of various organisms (as invertebrates and yeasts)

Other Words from hemoglobin

hemoglobinic or chiefly British haemoglobinic \ ˌhē-​mə-​glō-​ˈbin-​ik How to pronounce haemoglobinic (audio) \ adjective
hemoglobinous or chiefly British haemoglobinous \ -​ˈglō-​bə-​nəs How to pronounce haemoglobinous (audio) \ adjective

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More from Merriam-Webster on hemoglobin

Spanish Central: Translation of hemoglobin

Nglish: Translation of hemoglobin for Spanish Speakers

Britannica English: Translation of hemoglobin for Arabic Speakers

Britannica.com: Encyclopedia article about hemoglobin

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something of little or no value

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