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Identify the symptoms of low hemoglobin levels. Have your hemoglobin levels tested. Know the other medical conditions that could cause low hemoglobin.
Only a doctor can diagnose low hemoglobin levels. Your doctor will need to test your blood in order to give a proper diagnosis, and then potentially do other studies to determine the cause of your low hemoglobin. If you're experiencing severe symptoms of low hemoglobin, however,  you should see your doctor as soon as possible. Common symptoms of severely low hemoglobin levels include:  Weakness/fatigue Shortness of breath Fast/irregular heartbeat (palpitations) Paleness of the skin and/or gums The only way to confirm that you have a low hemoglobin level is by having your blood tested by a doctor. If you are experiencing any of the symptoms of low hemoglobin levels on a regular basis, see your doctor as soon as possible to determine the cause of your symptoms and develop a treatment plan.  Your doctor will most likely run a complete blood count test to confirm that you have a low hemoglobin count. To run the blood test, your doctor will need to collect a small sample of blood. You will be stuck with a needle, but it is not particularly painful, and any pain is very short-lived. Normal hemoglobin levels for adult men are between 13.8 and 17.2 grams per deciliter (g/dL). Normal hemoglobin levels for adult women are between 12.1 and 15.1 g/dL.  If the blood tests do not indicate low hemoglobin levels, your doctor will need to run further tests to determine what other medical issues could be causing your symptoms. Low hemoglobin levels can be caused by a number of underlying conditions. Any disease or condition that reduces your red blood cell count can result in low hemoglobin levels. Common conditions that cause low hemoglobin levels include:  Anemia (aplastic, iron deficiency, vitamin deficiency, and sickle cell) Cancer and certain non-cancerous tumors Chronic kidney disease Cirrhosis of the liver Enlarged spleen Lymphoma (both Hodgkin's and non-Hodgkin's) Hypothyroidism Internal bleeding Lead poisoning Leukemia Multiple myeloma Porphyria Reactions to HIV or chemotherapy medications Vasculitis