Dictionary

Labs and diagnostics

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

potassiumA mineral in the blood that nerves and muscles, including the heart, need in order to work.

PR intervalThe part of an ECG from the start of the P wave to the start of the QRS complex.

prealbuminA protein made by the liver, measured in the blood as one marker of protein nutrition.

prediabetesBlood sugar levels that are higher than normal but not yet high enough to be called diabetes.

procalcitoninA protein measured in the blood whose level rises sharply in response to bacterial infection.

prostate-specific antigenA protein made by the prostate gland, measured in a blood test to screen for and follow prostate problems.

proteinA nutrient made of chains of amino acids that the body uses to build and repair tissue.

proteinuriaMore protein in the urine than normal.

prothrombin timeA blood test that measures how many seconds it takes a blood sample to form a clot.

pulmonary function testsBreathing tests that measure how much air the lungs hold and how fast air moves in and out.

pulse oximetryA painless test that uses light through a finger, toe or earlobe to estimate how much oxygen the blood is carrying.

QRS complexThe tall, spiky wave on an ECG that shows the electrical signal spreading through the ventricles.

radiopaqueBlocking x-rays, so the material shows up white on an x-ray image.

rapid plasma reaginA blood test used to screen for syphilis by looking for antibodies the body makes during the infection.

red blood cellA blood cell that carries oxygen from the lungs to the body's tissues; also called an erythrocyte.

red blood cell countA blood test that counts the red blood cells in a set amount of blood.

reference rangeThe range of results for a lab test that is expected in healthy people, also called the normal range.

respiratory acidosisA state in which the blood becomes too acidic because the lungs do not remove enough carbon dioxide.

respiratory alkalosisAn acid-base imbalance in which breathing out too much carbon dioxide makes the blood too alkaline.

reticulocyte countA blood test that measures reticulocytes, young red blood cells newly released from the bone marrow.

Rh factorA protein that may be present on the surface of red blood cells; people who have it are Rh-positive and those without it are Rh-negative.

RT-PCRReverse transcription polymerase chain reaction: a lab test that finds the genetic material of a virus or other germ in a sample.

samplingTaking a small part of something, such as blood or tissue, or choosing a group of people for a study.

saturationHow full something is; in nursing, usually the percentage of hemoglobin in the blood that is carrying oxygen.

scrapingA sample of cells collected by gently scraping a surface such as the skin, or the act of collecting it.

screeningTesting people who have no symptoms to find a disease or risk early.

screening testA test given to people who have no symptoms, to find a disease or risk early.

sensitivityHow strongly something responds; in lab work, which drugs stop a germ, or how well a test finds people who have a disease.

serumThe clear, yellow liquid left from blood after it clots and the cells are removed.

serum ironA blood test that measures the amount of iron carried in the blood.

serum ketonesA blood test for ketones, acids the body makes when it burns fat for energy instead of sugar.

serum osmolalityA blood test that measures how concentrated the blood is, by the amount of dissolved particles in it.

sinus rhythmA heart rhythm that starts in the sinoatrial node, the heart's natural pacemaker.

smearA thin layer of a sample, such as blood or cells, spread on a glass slide to be looked at under a microscope.

sodiumA mineral in the blood that controls how water moves in the body and helps nerves and muscles work.

specimenA sample of blood, urine, stool, tissue or other body material collected for testing.

SPECTSingle-photon emission computed tomography: a nuclear medicine scan that makes 3D pictures using a small dose of a radioactive tracer.

spirometerA device that measures how much air a person breathes in or out, and how fast.

sputumMucus and other material coughed up from the lungs and lower airways.

sputum cultureA lab test that grows germs from mucus coughed up from the lungs, to find out which germ is present.

steeple signA tapered narrowing of the upper airway below the vocal cords that looks like a church steeple on a front-view neck x-ray.

stool cultureA lab test that grows germs from a stool sample to find the bacteria causing an infection.

sweat chloride testA test that measures the amount of chloride in sweat collected from the skin.

T waveThe wave on an electrocardiogram that shows the heart's lower chambers recovering electrically after each beat.

T3Triiodothyronine: the more active of the two main thyroid hormones, or the blood test that measures it.

theophylline levelA blood test that measures how much of the bronchodilator theophylline is in the blood.

therapeutic rangeThe span of blood levels of a drug that is high enough to work but low enough to avoid toxic effects.

thoracentesisA procedure in which a needle is passed through the chest wall to remove fluid or air from the space around a lung.

throat cultureA test in which a swab of the back of the throat is grown in the lab to find which bacteria are there.

thrombocytopeniaA blood platelet count below normal, under 150,000/mm3.