Haemoglobin vs. Hemoglobin — What's the Difference?

Haemoglobin, often spelled in British English, and hemoglobin, its American English counterpart, are terms that denote the same essential protein found in the red cells of many vertebrates. This protein is crucial for transporting oxygen from the lungs to the rest of the body and returning carbon dioxide back to the lungs to be exhaled.

The primary structure of haemoglobin involves four polypeptide chains and iron-containing heme groups that bind oxygen. Hemoglobin, by any spelling, functions similarly across all animals that possess it, facilitating the exchange of gases necessary for cellular metabolism.

In medical and scientific literature, the usage of "haemoglobin" versus "hemoglobin" can denote the regional origin of the publication or the preference of the publication's editorial standards. For instance, journals based in the UK are more likely to use "haemoglobin," while those in the US will typically use "hemoglobin."

Despite the different spellings, there is no difference in the interpretation or understanding of the protein's function in biology and medicine. Whether in a British or American context, the protein's role and importance in physiology and medical diagnostics, such as in measuring health and function, remain consistent.