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Normal hemoglobin is 13.8–17.2 g/dL in men and 12.1–15.1 g/dL in women.
Hemoglobin is the oxygen-carrying molecule found inside red blood cells. It picks up oxygen in the lungs and delivers it to the tissues as it flows around the body. Having a low hemoglobin level is a sign of anemia. It can result from a number of things, including blood loss, genetic disorders, and nutritional deficiencies (such as iron deficiency). Symptoms of anemia include weakness, fatigue, lightheadedness, pale skin, and shortness of breath. Having a high hemoglobin level can be a sign of polycythemia vera, in which the bone marrow makes too many red blood cells. It can also occur in situations in which the body needs help getting oxygen to the tissues, such as in people with lung disease, people who smoke, and people living at high elevation. Bringing hemoglobin levels back into the normal range requires addressing the underlying cause.
What we mean by normal
In medicine, using the term “normal” can sometimes be off-putting. Saying something is “normal” implies that everything else is “abnormal.” Additionally, saying something is “normal” may not be accurate, since something that is “normal” for you may not be “normal” for somebody else. Therefore, instead of saying certain values are “normal,” alternative terminology may be to say that these values are “healthy” or “within the reference range.”
Additionally, some values have well-defined cutoffs, while others do not. For example, when looking at hemoglobin A1c levels, a value of 6.5 or greater is always diagnostic of diabetes. On the other hand, when looking at testosterone levels, some use cutoffs of 270–1,070 ng/dL while others use cutoffs of 300–1,000 ng/dL.
The information above represents values that are commonly used as cutoffs. However, depending on the specific source you’re looking at or the laboratory you go to, their values may be a little different.
Dr. Tzvi Doron is Board Certified in Family Medicine by the American Board of Family Medicine and is Ro's Chief Clinical Officer.