Glossary of Terms - p

Index

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Terms

Panel testing: A laboratory procedure in which a series of tests is performed on one specimen, usually related to a single condition or disease, or for differential diagnosis.
PCP: See phencyclidine hydrochloride.
Pelvic inflammatory disease (PID): Ascending infection from the vagina or cervix to the uterus, fallopian tubes and broad ligaments: most often caused by bacterial infections of chlamydia and gonorrhea.
Pelvic node dissection: Removal of possible cancer carrying lymph nodes near the prostate or their evaluation.
PET scan: See positron emission tomography.
Phencyclidine hydrochloride (PCP): An anesthetic agent used in veterinary medicine. Also an illegal hallucinogenic street drug, "angel dust." Its presence may be detected by urine testing.
Phenytoin: An anticonvulsant drug used to treat seizure disorders including epilepsy, as well as digitalis-induced heartbeat rhythm disturbances. An overdose can have toxic effects. A blood test can determine the phenytoin level to aid in correct dosing and avoid toxicity.
Phosphorus (P): An element required for bone growth and metabolic energy. Stored in teeth and bones, mainly in combination with calcium, phosphorus blood levels are affected by parathyroid, blood, and bone diseases.
Photon: A unit or particle of radiant or light energy. Photons have no electric charge. Gamma and X-rays may be referred to as photons.
Pipettes: Calibrated devices used for liquid measurement.
Pituitary: A bi-lobed endocrine gland located at the base of the brain that secretes several critical hormones for the regulation of other endocrine glands, including the secretion of TSH for stimulation of the thyroid. The pituitary is regulated by the neurohormones from the hypothalamus.
Plasma: The watery fluid portion of blood in which the corpuscular elements are suspended. It transports nutrients as well as wastes throughout the body. Various compounds — including proteins, electrolytes, carbohydrates, minerals, and fats — are dissolved in it.
Polydipsia: A chronic excessive intake of water; a characteristic of uncontrolled diabetes mellitus.
Polyphagia: Excessive eating or hunger, a characteristic of uncontrolled diabetes mellitus.
Polyuria: The passage of a large amount of urine in a given period, a characteristic of diabetes mellitus.
Positron emission tomography (PET): A computerized radiographic technique that shows metabolic activity occurring in various body structures (in the heart and brain, for example). A radioactive substance that emits positively charged electrons (positrons) is injected into or inhaled by the patient, in whom they combine with negatively charged electrons. The resulting gamma radiation is converted into color-coded images.
Postpartum Thyroiditis: An autoimmune condition resulting in transient thyrotoxicosis followed by hypothyroidism occurring after parturition (giving birth). It may recur with subsequent pregnancies.
Potassium (K): An essential element found primarily in the cells of the body. It helps to maintain proper muscle and nerve function; it also helps in some important metabolic processes. Blood serum potassium levels usually are determined to help evaluate heart rhythm irregularities, neuromuscular disorders and kidney function.
Precision: Reproducibility, the agreement of data points (test results) when a test is run more than once.
Primary wavelength: The wavelength at which a chemistry has the greatest absorbance.
Prostate specific antigen test: A blood test which measures a patient's level of prostate specific antigen. If elevated, the antigens may be an indicator of prostate cancer.
Prostate specific antigen(PSA): A substance manufactured mainly by the prostate.
Prostatectomy: Surgical removal of the prostate.
Prostatic acid phosphatase test: A blood substance that rises above normal in many patients when prostate cancer has spread beyond the prostate.
Prothrombin: A plasma protein, one of the coagulation factors and the precursor of thrombin, prothrombin is synthesized in the liver with the help of vitamin K. The prothrombin time (PT) test measures blood clotting time, evaluates bleeding disorders and liver damage, and monitors the use of anticoagulant drugs.