Article: Urinalysis

A urinalysis (or "UA") is an array of tests performed on urine and one of the most common methods of medical diagnosis. A part of a urinalysis can be performed by using urine dipsticks, in which the test results can be read as color changes.

Medical urinalysis

A typical medical urinalysis usually includes:

  • a description of color and appearance
  • specific gravity
  • pH
  • glucose
  • ketones
  • protein
  • RBC number
  • WBC number
  • The hormone hCG: Pregnancy may be checked for by screening a woman's urine for this. Home testing Pregnancy tests have been developed for this purpose.
  • Pyroluria

Microscopic examination

The numbers and types of cells and/or debris present can yield a great detail of information and may suggest a specific diagnosis.

  • eosinophiluria - associated with allergic interstitial nephritis, atheroembolic disease
  • RBC casts - associated with glomerulonephritis, vasculitis, malignant hypertension
  • WBC casts - associated with acute interstitial nephritis, exudative glomerulonephritis, severe pyelonephritis
  • (heme) granular casts - associated with acute tubular necrosis
  • crystalluria -- associated with acute urate nephropathy (or "Acute uric acid nephropathy", AUAN)
  • calcium oxalate - associated with ethylene glycol toxicity

Forensic urine drug screening

Drug testing uses urinalysis to test for certain chemicals which are typically present in the urine only after recreational drug use. These tests must be requested specifically or as part of a toxicology screen, and are not part of a routine urinalysis. Such tests are sometimes even requested for employment reasons, whereby a certain organization seeks to avoid hiring people using certain drugs, either for safety reasons (as in the case when a person is employed to operate dangerous machinery) or for legal and public relations reasons, as several common types of drug use are officially forbidden in much of the world. This controversial practice is not always legal and an employer can legally not discriminate against someone solely on the basis that he refuses a drug test. More often, these tests are performed at the behest of the legal system--by a police or probation officer, by court order, or as part of a court-ordered drug treatment program. The legality of these drug tests has been questioned in the United States under the Fifth Amendment.

Ethical and moral concerns have been raised concerning the propriety of forbidding individuals to use recreational drugs in their free time, when not actually working, by testing for any drug use at all within a long time frame (the hair may be tested for drug residue that is months or years old); and for opening the possibility of other tests (such as a pregnancy test) being performed without the person's knowledge or consent.

Sports teams frequently check for barred muscle-building drugs such as anabolic steroids via urinalysis, and various schools and parents have drug tested their children to check for illegal drug use, particularly marijuana smoking in teenagers. This has lead to concerns over the civil rights of the people tested, quite often in circumstances where a refusal to provide a sample will lead to a presumption that the test would have proved positive. This denies the test subjects' their right to avoid self-incrimination and in many cases in school, their right to education as the refusal to provide a sample can lead to exclusion and expulsion from school.

"U.A." is sometimes used as a shorthand way of referring to urinalysis, especially among people who have to take the test frequently, such as participants in a drug treatment program.

Problems With Urine Testing

Because it is important to be certain that the sample of urine provided, is actually produced by the person being tested, it is necessary to verify that and this is often achieved by requiring direct observation of the production of the sample. It is becoming increasingly evident that there is a problem with this, because a significant number of individuals experience a psychological problem called Paruresis, where, against the will of the sufferer, the ability to urinate is physically over-ridden by the nervous system, in circumstances, which include lack of privacy. A growing number of organisations are catering for this in various ways as are desribed in the article on Paruresis.

See also

  • uroscopy, the ancient form of this analysis