Dictionary

Labs and diagnostics

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

lactic acidosisA type of metabolic acidosis in which lactic acid (lactate) builds up in the blood.

late decelerationA gradual drop in the fetal heart rate that starts and hits its lowest point after the peak of a contraction.

lecithin/sphingomyelin ratioA test of amniotic fluid that compares two fats found in lung surfactant, used to judge whether a fetus's lungs are mature.

lipaseAn enzyme, made mainly by the pancreas, that breaks down fats; its blood level is a common lab test.

lipidA fat or fat-like substance in the body or food, such as cholesterol and triglycerides.

lipid panelA blood test that measures fats in the blood: total cholesterol, LDL and HDL cholesterol, and triglycerides.

lipoproteinA particle made of fat and protein that carries cholesterol and other fats through the blood.

literA metric unit of volume equal to 1,000 milliliters, a little more than a US quart.

lithium levelA blood test that measures how much of the mood-stabilizing drug lithium is in the blood.

liver function testsA group of blood tests that check how well the liver is working and whether its cells are damaged.

low-density lipoproteinA particle that carries cholesterol in the blood; its level is measured in a lipid panel and is often called "bad" cholesterol.

lumbar punctureA procedure in which a needle is put between two bones in the lower back to take out spinal fluid or give medicine; a spinal tap.

lymphocyteA type of white blood cell that targets specific germs and abnormal cells, including T cells, B cells and natural killer cells.

magnesiumA mineral in the blood that the nerves, muscles and heart need, measured with a blood test.

magnetic resonance imagingAn imaging test that uses a strong magnet and radio waves to make detailed pictures of the inside of the body.

mammogramAn x-ray picture of the breast, used to screen for and look into breast cancer.

markerSomething that can be measured, such as a substance in the blood, that shows a disease or body process is present.

mean arterial pressureThe average pressure in the arteries over one heartbeat, used as a measure of how well blood reaches the organs.

mean corpuscular volumeThe average size of a person's red blood cells, reported as part of a complete blood count.

mEqMilliequivalent: a unit for the amount of an electrolyte, based on its electrical charge.

metabolic acidosisA state in which the blood is too acidic because the body has too much acid or has lost too much bicarbonate.

metabolic alkalosisAn acid-base imbalance in which the blood holds too much bicarbonate, so its pH rises above 7.45.

mg/dLMilligrams per deciliter: a unit that shows how much of a substance is in one tenth of a liter of blood or fluid.

microalbuminA urine test for small amounts of the protein albumin, usually reported as the urine albumin-to-creatinine ratio.

microbiologyThe study of microorganisms such as bacteria, viruses, fungi and parasites; also the lab that tests for them.

mm HgMillimeters of mercury: the unit used to measure blood pressure and the pressure of gases in the blood.

mmolMillimole: a unit for an amount of a substance, often given per liter of blood (mmol/L) in lab results.

mOsmMilliosmole: a unit for the number of dissolved particles in a fluid, used for osmolality.

natriuretic peptideA hormone released by stretched heart muscle that makes the kidneys remove sodium and water and relaxes the blood vessels.

NCSNerve conduction study: a test that measures how fast and how strongly electrical signals travel along a nerve.

neutropeniaA lower than normal number of neutrophils, the white blood cells that fight bacterial infection first.

neutrophilThe most common type of white blood cell, which is first to reach and destroy bacteria at a site of infection.

newborn screeningTesting of every newborn for serious hidden conditions, using a few drops of blood from the heel plus hearing and heart checks.

ng/mLNanograms per milliliter: a unit for very small amounts of a substance in blood or another fluid.

nonstress testA prenatal test that records the fetal heart rate for about 20 to 40 minutes to see how it changes when the baby moves.

NT-proBNPA blood test for a protein the heart's ventricles release when they are stretched, used in the diagnosis and follow-up of heart failure.

oral glucose tolerance testA blood test that measures blood sugar before and at set times after drinking a measured sweet glucose drink.

osmolarityThe amount of dissolved particles in a set volume of fluid, which decides which way water moves.

oximetryMeasuring how much of the blood's hemoglobin is carrying oxygen.

PaCO2The partial pressure of carbon dioxide in arterial blood, measured in a blood gas test.

PaO2The partial pressure of oxygen in arterial blood: a measure of how much oxygen is dissolved in the blood, from an arterial blood gas.

Pap testA screening test in which cells are gently scraped from the cervix and looked at under a microscope.

pathologyThe study of disease and its causes and effects, or the disease changes found in a person or tissue.

PCRPolymerase chain reaction: a lab method that copies tiny amounts of genetic material so a germ or a gene can be detected.

peak and trough levelsBlood tests of a drug's highest level after a dose (peak) and its lowest level just before the next dose (trough).

pg/mLPicograms per milliliter: a unit for very small amounts of a substance in a fluid.

phenytoin levelA blood test that measures how much of the antiseizure drug phenytoin is in the blood.

phosphorusA mineral in the blood and bones, measured as phosphate, that works with calcium to build bone and supply energy to cells.

plateletA tiny cell fragment in the blood that sticks together at a wound to help form a clot.

positron emission tomographyAn imaging test that uses a small amount of a radioactive tracer to show how active the body's tissues are.