• Disease

    Hairy cell leukemia

    A small amount of bone marrow is removed during a bone marrow aspiration.  The procedure is uncomfortable, but can be tolerated by both children and adults.  The marrow can be studied to determine the cause of anemia, the presence of leukemia or other malignancy, or the presence of some "storage diseases" in which abnormal metabolic products are stored in certain bone marrow cells.

    Hairy cell leukemia (HCL) is an unusual cancer of the blood. It affects B cells, a type of white blood cell (lymphocyte).

  • Test

    Ham test

    The Ham test is a blood test done to diagnose (PNH). The test checks whether red blood cells become more fragile when they are placed in mild acid.

  • Test

    Haptoglobin blood test

    The haptoglobin blood test measures the level of haptoglobin in your blood. Haptoglobin is a protein produced by the liver. It attaches to a certain type of in the blood.

  • Test


    Blood transports oxygen and nutrients to body tissues and returns waste and carbon dioxide. Blood distributes nearly everything that is carried from one area in the body to another place within the body. For example, blood transports hormones from endocrine organs to their target organs and tissues. Blood helps maintain body temperature and normal pH levels in body tissues. The protective functions of blood include clot formation and the prevention of infection.

    Hematocrit is a blood test that measures the percentage of the volume of whole blood that is made up of red blood cells. This measurement depends on and the size of red blood cells.

  • Disease


    Hepatomegaly is enlargement of the liver beyond its normal size.  Certain conditions such as infection, parasites, tumors, anemias, toxic states, storage diseases, heart failure, congenital heart disease, and metabolic disturbances may all cause an enlarged liver.

    Hemochromatosis is a condition in which there is too much iron in the body. It is also called iron overload.

  • Test


    Hemoglobin is the most important component of red blood cells. It is composed of a protein called heme, which binds oxygen. In the lungs, oxygen is exchanged for carbon dioxide. Abnormalities of an individual's hemoglobin value can indicate defects in the normal balance between red blood cell production and destruction. Both low and high values can indicate disease states.

    The hemoglobin test is a blood test that measures how much hemoglobin is your blood. Hemoglobin is a protein in red blood cells that carries oxygen.

  • Disease

    Hemoglobin C disease

    Blood is comprised of red blood cells, platelets, and various white blood cells.

    Hemoglobin C disease is a blood disorder passed down through families. It leads to a type of anemia, which occurs when red blood cells break down earlier than normal.

  • Test

    Hemoglobin electrophoresis

    This lab test measures the levels of the different types of the oxygen-carrying protein () in the blood.

  • Disease


    Hemoglobinopathy is a group of disorders passed down through families (inherited) in which there is abnormal production or structure of the molecule. Such disorders include , hemoglobin S-C disease, , and various types of .

  • Special Topic


    Hemolysis is the breakdown of red blood cells. See also:

  • Disease

    Hemolytic anemia

    Sickle cell anemia is an inherited blood disease in which the red blood cells produce abnormal pigment (hemoglobin). The abnormal hemoglobin causes deformity of the red blood cells into crescent or sickle-shapes, as seen in this photomicrograph.

    is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Normally, red blood cells last for about 120 days in the body. In hemolytic anemia, red blood cells in the blood are destroyed earlier than normal.

  • Disease

    Hemolytic anemia caused by chemicals and toxins

    caused by chemicals and toxins is a lack of red blood cells that occurs when red blood cells are excessively damaged by certain chemicals or toxins.

  • Symptoms

    Hemolytic crisis

    Hemolytic crisis is the rapid destruction of large numbers of red blood cells (). The destruction occurs much faster than the body can produce new red blood cells.

  • Disease

    Hemolytic-uremic syndrome

    The urinary system is made up of the kidneys, ureters, urethra and bladder.

    Shiga-like toxin producing E. coli hemolytic-uremic syndrome (STEC-HUS) is a disorder that usually occurs when an infection in the digestive system produces toxic substances that destroy red blood cells, causing kidney injury.

  • Disease


    Blood clots (fibrin clots) are the clumps that result when blood coagulates.

    Hemophilia refers to a group of bleeding disorders in which blooding takes a long time. Some types of disorder include: Hemophilia A Hemophilia B Von Willebrand disease

  • Disease

    Hemophilia A

    Blood clots (fibrin clots) are the clumps that result when blood coagulates.

    Hemophilia A is a hereditary caused by a lack of blood clotting factor VIII. Without enough factor VIII, the blood cannot clot properly to stop bleeding.

  • Disease

    Hemophilia B

    There are several X-linked (or sex-linked) recessive genetic disorders, (hemophilia, muscular dystrophy) which are inherited through a genetic defect on an X chromosome. A female has 2 X chromosomes, one she inherited from her mother and one she got from her father. A male has an X chromosome from his mother and a Y chromosome from his father. Since male offspring receive their X chromosome from their mothers, the inheritance of a defect attached to that one copy of the X  will cause the disorder.

    Hemophilia B is a hereditary bleeding disorder caused by a lack of blood clotting factor IX. Without enough factor IX, the blood cannot clot properly to control bleeding. See also:

  • Disease

    Hereditary elliptocytosis

    Blood is comprised of red blood cells, platelets, and various white blood cells.

    Hereditary elliptocytosis is a disorder passed down through families in which the red blood cells are abnormally shaped. See also:

  • Disease

    Hereditary ovalocytosis

    Red blood cells (RBCs) are normally round.  In ovalocytosis, the cells are oval.  Other conditions that produce abnormally shaped RBCs include spherocytosis and eliptocytosis.

    Hereditary ovalocytosis is a rare condition passed down through families (inherited). The blood cells are oval-shaped instead of round. It is a form of hereditary elliptocytosis.

  • Disease

    Hodgkin lymphoma

    The lymphatic system filters fluid from around cells.  It is an important part of the immune system.  When people refer to swollen glands in the neck, they are usually referring to swollen lymph nodes.  Common areas where lymph nodes can be easily felt, especially if they are enlarged, are: the groin, armpits (axilla), above the clavicle (supraclavicular), in the neck (cervical), and the back of the head just above hairline (occipital).

    Hodgkin lymphoma is a cancer of lymph tissue. Lymph tissue is found in the lymph nodes, spleen, liver, bone marrow, and other sites.

  • Test


    A decrease in the amount of hemoglobin found in red blood cells is called hypochromia.

    Hypochromia means that the red blood cells have less color than normal when examined under a microscope. This usually occurs when there is not enough of the pigment that carries oxygen () in the red blood cells. The most common cause of hypochromia in the United States is not enough iron in the body ...