From Wikipedia, the free encyclopedia

A medical test is any kind of diagnostic medical procedure performed for health reasons. For example:

• to diagnose diseases
• to measure the progress or recovery from disease
• to confirm that a person is free from disease

A drug test can be a specific medical test to acertain the presence of a certain drug in the body (for example, in drug addicts).

Contents 1 Properties 1.1 Bayesian probability and performance metrics 1.2 Psychological effects of diagnostic tests 2 Overview 2.1 Consulting room tests 2.2 More invasive examinations requiring sterile procedures 2.3 Requiring laboratory analysis 2.4 Requiring microscopy 2.5 Requiring elaborate medical equipment 3 See also 4 References 5 External links

The result of a test may be positive or negative: this has nothing to do with a bad prognosis, but rather means that the test worked or not, and a certain parameter that was evaluated was present or not. For example, a negative screening test for breast cancer means that no sign of breast cancer could be found (which is in fact very positive for the patient).

Other characteristics of tests include:

• sensitivity
• specificity
• positive predictive value
• negative predictive value
• false positive
• false negative

Medical tests can have value when results are abnormal by explaining to a patient the cause of their symptoms^[1]. In addition, normal test results can have value by reassuring patients that serious illness is not present and even reduce the rates of subsequent symptoms ^[2]. Understanding the meaning of a normal test in advance of learning the test results may also reduce the rates of subsequent symptoms ^[3].

Lack of inadequate education about the meaning of test results (especially relevant to tests that may have incidental and unimportant findings) may cause an increase in symptoms ^[4]. In addition, the possible benefits must be weighed against the costs of unnecessary tests and resulting unnecessary follow-up and possibly even unnecessary treatment of incidental findings ^[5].

Some medical tests are parts of a simple physical examination which require only simple tools in the hands of a skilled practitioner, and can be performed in an office environment. Some other tests require elaborate equipment or the use of a sterile operating theatre environment.

Some tests require samples of tissue or body fluids to be sent off to a pathology lab for further analysis. Some simple chemical tests, such as urine pH, can be measured directly in the doctor's office.

Most medical tests are conducted on the living; however, some of these tests can also be carried out on a dead person as part of an autopsy.

Medical tests can be classified into three categories:

• invasive
• minimally invasive
• non-invasive

Types of medical tests include:

• auscultation, including listening with a stethoscope
• weighing, and measuring height and girth
• measuring blood pressure
• taking the patient's pulse
• breath tests
• reflex tests
• eye examination
  • ophthalmoscopy
• hearing test
• digital rectal examination
• vaginal examination

• biopsies
• lumbar puncture

• urine tests
• stool samples
• saliva samples
• hair samples
• blood tests
  • ESR
  • CBC (complete blood count)
• blood gas monitor
• DNA tests

• Pap smears

• X-rays
  • barium enema
  • intravenous pyelogram (IVP test)
• ultrasound scans
• electrocardiogram (EKG)
• electroencephalogram (EEG)
• computer aided tomography scans
  • positron emission tomography
  • magnetic resonance imaging (MRI)
    • functional MRI
• endoscopy
  • colonoscopy
  • cystoscopy
  • sigmoidoscopy
  • colposcopy

• Medical record
• Physical examination

1. ^ Ward B, Wu W, Richter J, Hackshaw B, Castell D (1987). "Long-term follow-up of symptomatic status of patients with noncardiac chest pain: is diagnosis of esophageal etiology helpful?". Am J Gastroenterol 82 (3): 215-8. PMID 3826028. 
2. ^ Sox H, Margulies I, Sox C (1981). "Psychologically mediated effects of diagnostic tests". Ann Intern Med 95 (6): 680-5. PMID 7305144. 
3. ^ Petrie K, Müller J, Schirmbeck F, Donkin L, Broadbent E, Ellis C, Gamble G, Rief W (2007). "Effect of providing information about normal test results on patients' reassurance: randomised controlled trial". BMJ 334: 352. PMID 17259186. 
4. ^ Kendrick D, Fielding K, Bentley E, Kerslake R, Miller P, Pringle M (2001). "Radiography of the lumbar spine in primary care patients with low back pain: randomised controlled trial". BMJ 322 (7283): 400-5. PMID 11179160. 
5. ^ Jarvik J, Hollingworth W, Martin B, Emerson S, Gray D, Overman S, Robinson D, Staiger T, Wessbecher F, Sullivan S, Kreuter W, Deyo R (2003). "Rapid magnetic resonance imaging vs radiographs for patients with low back pain: a randomized controlled trial". JAMA 289 (21): 2810-8. PMID 12783911. 

• Diagnostic medical tests - Informative, educational and user- friendly web site that offers valuable information about laboratory services, diagnostic and medical tests with comprehensive references and information.

• Detecting breast cancer earlier - Breast cancer research foundation web site. Information on breast cancer medical researches that demonstrates the potential for discovering earlier methods of detecting breast cancer.