Find answers to your health-related questions in our health encyclopedia.

  • Test


    5-HIAA is a urine test that measures the amount of 5-hydroxyindoleacetic acid (5-HIAA). 5-HIAA is a breakdown product of a hormone called serotonin. This...

  • Special Topics

    8 ways to cut health care costs

  • Special Topics

    A guide to clinical trials for cancer

  • Special Topics

    A guide to help children understand cancer

  • Special Topics

    A guide to herbal remedies

  • Test

    A1C test

    Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.

    A1C is a lab test that shows the average level of blood sugar (glucose) over the previous 3 months. It shows how well you are controlling your diabetes.

  • Disease

    Aarskog syndrome

    The physical landmarks of the human face are very similar from one face to another.

    Aarskog syndrome is a disease that affects a person’s height, muscles, skeleton, genitals, and appearance. It is passed down through families (inherited).

  • Disease

    Aase syndrome

    Aase syndrome is a rare disorder that involves anemia and certain joint and skeletal deformities.

  • Symptoms

    Abdomen - swollen

    A swollen abdomen is when your belly area is bigger than usual.

  • Disease

    Abdominal aortic aneurysm

    Abdominal aortic aneurysm involves a widening, stretching, or ballooning of the aorta. There are several causes of abdominal aortic aneurysm, but the most common results from atherosclerotic disease. As the aorta gets progressively larger over time there is increased chance of rupture.

    The aorta is the main blood vessel that supplies blood to the abdomen, pelvis, and legs. An abdominal aortic aneurysm occurs when an area of the aorta...