Glossary try the best to avoid the use of medical terms that could make it more difficult to understand the information on this website. Still, there are a number of terms that can't be avoided and that are useful to know because they are so often used by the doctors, nurses, and other medical professionals with whom you might speak. The list below includes the terms used on for which we have provided definitions.

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Term Definition

Genetic; passed from parent to offspring

Heterophile Antibody

A human antibody that reacts with proteins from another species; may lead to innaccurate results in immunoassay tests; sometimes used to refer to antibodies associated with infectious mononucleosis


Having two different copies of a particular gene, one of which may be abnormal


Abnormal hairiness, especially an adult male pattern of hair distribution in a female

Human leukocyte antigens

Also known as: HLA

Group of proteins present on the surface of white blood cells (leukocytes) and other nucleated cells (containing a nucleus). These proteins help the body’s immune system to identify its own cells and to distinguish between “self” and “nonself.” Each person has an inherited combination of HLA antigens and, while not as unique as a fingerprint, the presence or absence of each antigen creates a distinctive HLA combination for each person. HLA antigens are divided into types: Class I (A, B, C) and Class II (DR, DP, DQ).


A condition in which the chambers (ventricles) within the brain become enlarged due to an abnormal accumulation of cerebrospinal fluid


Retaining excessive amounts of fluids


Higher than normal calcium level in the blood


Higher than normal glucose levels in the blood


Elevated levels of insulin in the blood


Higher than normal potassium levels in the blood


Higher than normal cholesterol and/or triglyceride levels in the blood


Higher than normal lipoprotein levels in the blood


Higher than normal sodium levels in the blood


A condition characterized by an overproduction of parathyroid hormone (PTH), a hormone that controls calcium and phosphate levels in blood and calcium in bone; it is made by the parathyroid glands. Primary hyperparathyroidism causes high calcium and low phosphate levels, and can cause kidney stones occasionally. Secondary hyperparathyroidism is caused by low levels of calcium or vitamin D, or high levels of phosphate; it is commonly caused by chronic kidney disease. Either form can cause osteoporosis or bone pain.