A low hemoglobin count is a commonly seen blood test result. Hemoglobin (Hb or Hgb) is a protein in red blood cells that carries oxygen throughout the body.
In many cases, a low hemoglobin count is only slightly lower than normal and doesn't affect how you feel. If it gets more severe and causes symptoms, your low hemoglobin count may indicate you have anemia.
A low hemoglobin count is generally defined as less than 13.5 grams of hemoglobin per deciliter (135 grams per liter) of blood for men and less than 12 grams per deciliter (120 grams per liter) for women. In children, the definition varies with age and sex. The threshold differs slightly from one medical practice to another.
A slightly low hemoglobin count isn't always a sign of illness — it may be normal for some people. Women who are pregnant commonly have low hemoglobin counts.
Hemoglobin tests are given for many reasons, such as to screen for or help diagnose disease and to monitor treatment response. Some people learn that their hemoglobin is low when they go to donate blood. If you're told that you can't donate blood because of low hemoglobin, make an appointment with your doctor.
Make an appointment if you have signs and symptoms
If you experience signs and symptoms of a low hemoglobin count, make an appointment with your doctor. Signs and symptoms may include:
- Pale skin and gums
- Shortness of breath
- A fast or irregular heartbeat
Your doctor may recommend a complete blood count test to determine whether you have a low hemoglobin count or whether your signs and symptoms are caused by something else.
If your test reveals you have a low hemoglobin count, you will likely need more testing to determine the cause. Then your doctor can explain what this means for you.
May 08, 2015
- Hemoglobin. Lab Tests Online. www.labtestsonline.org. Accessed March 12, 2015.
- McPherson RA, et al. Erythrocytic disorders. In: Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa.: Saunders Elsevier; 2011. www.clinicalkey.com. Accessed March 13, 2015.
- Anemia in people with cancer. American Cancer Society. http://www.cancer.org/treatment/treatmentsandsideeffects/physicalsideeffects/anemia/anemia-in-people-with-cancer. Accessed March 12, 2015.
- Goldman L, et al. Approach to the anemias. In: Goldman's Cecil Medicine. 24th ed. Philadelphia, Pa.: Saunders Elsevier, 2012. http://www.clinicalkey.com. Accessed March 12, 2015.
- Schrier SL. Approach to the adult patient with anemia. http://www.uptodate.com/home. Accessed March 12, 2015.
- Friel TJ, et al. Hematologic manifestations of HIV infection: Anemia. http://www.uptodate.com/home. Accessed March 13, 2015.
- Kellerman RD. Hematology. In: Conn's Current Therapy 2015. Philadelphia, Pa.: Saunders Elsevier; 2015. www.clinicalkey.com. Accessed March 12, 2015.