Hemoglobin is the protein in your red blood cells that carries oxygen around your body. A low level is one of the main ways anemia shows up on a blood test. Here is how to read yours.
Hemoglobin is the iron-rich protein inside red blood cells that binds oxygen in your lungs and carries it to the rest of your body. It is measured as part of a complete blood count, or CBC, and is reported in grams per decilitre (g/dL). It is one of the most useful single markers for spotting anemia.
Normal hemoglobin ranges differ by sex and by laboratory, so read your value against the range on your own report. A low hemoglobin often points toward anemia, meaning your blood is carrying less oxygen than it should. A high hemoglobin has its own set of causes. Your clinician interprets the number in context.
Anemia has many causes, including low iron, low vitamin B12, blood loss, and chronic conditions. Because the causes differ, a low hemoglobin usually prompts follow-up tests, such as ferritin or a look at red-blood-cell size, rather than an immediate conclusion. Symptoms can include tiredness and shortness of breath.
Upload your CBC and Mednex reads your hemoglobin alongside related markers in plain language, and tracks it over time.
Decode my labsContent last reviewed 9 July 2026. Reference ranges vary by laboratory; always read your results against the range printed on your own report.
This page explains a common lab marker in general terms using public information from the U.S. National Library of Medicine and other NIH sources. It is educational and is not a diagnosis or medical advice. Reference ranges differ between laboratories and the meaning of a result depends on your age, sex, medications, and overall health. Always discuss your own results with the clinician who ordered them.