What is the Color of Haemoglobin?
Haemoglobin is red. This protein, found in red blood cells, is responsible for carrying oxygen throughout the body and gives blood its characteristic red color.
The bright red color of oxygenated blood is directly attributed to haemoglobin. This protein binds to oxygen in the lungs, transforming into a bright red oxyhaemoglobin. Deoxygenated blood, while still red, appears a darker, more purplish hue. This difference in shade is due to the altered structure of haemoglobin when oxygen is not bound.
References Supporting Haemoglobin's Red Color:
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Multiple sources explicitly state that haemoglobin gives blood its red color. These include the provided text snippets from the Red Cross Blood Services, NCBI, University of Rochester Medical Center, NPR, and the Cleveland Clinic. These sources consistently identify the red color of blood as a direct consequence of the presence of haemoglobin.
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The reference stating, "Haemoglobin (Hb) is a protein found in the red blood cells that carries oxygen in your body and gives blood its red colour," directly confirms the color.
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Further supporting evidence comes from various sources explaining the role of iron in haemoglobin, a key component responsible for oxygen binding and the resulting red color.
Why the Misconception of Blue Blood?
Some people mistakenly believe that blood is blue in veins. This is incorrect. While deoxygenated blood appears darker, it is still red. The bluish appearance in veins is a result of the way light is scattered and absorbed by the skin and underlying tissues, not the actual color of the blood.
