Dictionary

Labs and diagnostics

Lab values with their normal and critical ranges, and the tests nurses prepare clients for.

gamma-glutamyl transferaseAn enzyme found mostly in the liver and bile ducts, measured in a blood test.

glomerular filtrationThe first step in making urine, when the kidneys' tiny filters let water and small substances pass out of the blood.

glomerular filtration rateHow much blood the kidneys filter each minute, used as the main measure of kidney function.

glucoseA simple sugar that is the body's main source of energy.

glucose challenge testA pregnancy screening test that measures blood glucose 1 hour after drinking a sweet glucose drink.

Gram stainA lab staining method that sorts bacteria into two groups by the color they turn under the microscope.

gram-negativeDescribes bacteria that stain pink or red with the Gram stain because of the way their cell wall is built.

gram-positiveDescribes bacteria that stain purple with the Gram stain because of their thick cell wall.

group B streptococcus screenA swab test in late pregnancy that checks the vagina and rectum for group B streptococcus bacteria.

hematocritA blood test that shows what share of the blood's volume is made up of red blood cells, given as a percentage.

hemoglobinThe iron-containing protein in red blood cells that carries oxygen, and the blood test that measures it.

hemoglobin A1CA blood test that shows a person's average blood sugar over the past 2 to 3 months.

hemolysisThe breaking apart of red blood cells, which releases hemoglobin into the blood.

hepatitis B surface antigenA blood test for a protein from the outer coat of the hepatitis B virus.

high-density lipoproteinA particle in the blood that carries cholesterol away from the arteries to the liver; its level is part of a lipid panel.

histologyThe study of body tissues under a microscope.

HIV testA blood or saliva test that looks for signs of the human immunodeficiency virus (HIV).

Holter monitorA small portable device that records the heart's electrical activity continuously, usually for 24 to 48 hours.

human chorionic gonadotropinA hormone made by the placenta during pregnancy, measured in blood or urine as a pregnancy test.

hyperbilirubinemiaToo much bilirubin, a yellow waste product of old red blood cells, in the blood.

hypercalcemiaA blood calcium level above normal.

hypercapniaToo much carbon dioxide in the blood, a PaCO2 above 45 mm Hg.

hyperchloremiaA blood chloride level above normal, over 106 mEq/L.

hyperglycemiaA blood glucose level above normal, over 100 mg/dL when fasting.

hyperkalemiaA blood potassium level above normal, over 5.0 mEq/L.

hyperlipidemiaHigher than healthy levels of fats (lipids), such as cholesterol or triglycerides, in the blood.

hypermagnesemiaA blood magnesium level above normal.

hypernatremiaA blood sodium level above normal, over 145 mEq/L.

hyperosmolarHaving more dissolved particles per unit of fluid than normal, so the fluid pulls water toward itself.

hyperphosphatemiaA blood phosphate (phosphorus) level above normal.

hypocalcemiaA blood calcium level below normal.

hypochloremiaA blood chloride level below normal, under 98 mEq/L.

hypoglycemiaA blood glucose level below normal, under 70 mg/dL.

hypokalemiaA blood potassium level below normal, under 3.5 mEq/L.

hypomagnesemiaA blood magnesium level below normal.

hyponatremiaA blood sodium level below normal, under 135 mEq/L.

hypophosphatemiaA blood phosphate (phosphorus) level below normal.

hypoxemiaA level of oxygen in the blood below normal.

IgMImmunoglobulin M: the antibody the body makes first when it meets a new infection.

imbalanceA lack of balance: too much or too little of something the body needs to keep at a steady level.

interferon-gamma release assayA blood test that shows whether a person has been infected with the bacteria that cause tuberculosis.

international normalized ratioA blood test result that shows how long blood takes to clot, reported in a standard way so labs everywhere can compare it.

intervalThe time or space between two events, such as between two contractions in labor or between two waves on an ECG.

ionized calciumA blood test for the free, active form of calcium that is not bound to proteins.

Kerley B linesShort, thin horizontal lines near the outer edges of the lower lungs on a chest x-ray.

ketoacidosisA state in which ketones build up in the blood and make it too acidic.

ketoneAn acid made by the liver when the body burns fat for energy instead of glucose.

laboratoryA place where samples such as blood, urine or tissue are tested, or the tests that are done there.

lactateA substance made when cells break down glucose for energy; its blood level is a common lab test.

lacticRelating to milk, or to lactic acid, a substance cells make when they break down glucose without enough oxygen.