Dictionary

Labs and diagnostics

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

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.

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.