Blood test

From Free net encyclopedia

Blood tests are laboratory tests done on blood to gain an appreciation of disease states and the function of organs. Since blood flows throughout the body, acting as a medium for providing oxygen and other nutrients, and drawing waste products back to the excretory systems for disposal, the state of the bloodstream affects, or is affected by, many medical conditions. For these reasons, blood tests are the most commonly performed medical tests. Blood is obtained from a patient by venipuncture, except for tests such as Arterial blood gas.

Blood is useful as it is a relatively non-invasive way to obtain cells, and extracellular fluid (plasma), from the body to check on its health. Although the term blood test is used, most routine tests (except for most haematology) are done on plasma or serum.

The list below includes both specific tests, and general techniques.

Contents 1 Blood chemistry tests 2 Large organic molecules 2.1 proteins 2.1.1 Antibody proteins 2.2 Other 3 Cells 4 External links 5 See also

Blood chemistry tests

The CHEM-7 test is a battery of blood chemistry tests. The seven parts of a CHEM-7 include tests for:

• Four electrolytes:
  • sodium [1]
  • potassium [2]
  • chloride [3]
  • bicarbonate or CO₂ [4]
• blood urea nitrogen (BUN) [5]
• creatinine [6]
• glucose [7]. (This test can also be performed directly by diabetic patients by using a glucose meter.)

One common use for these tests is to determine renal function.

While the regular glucose test is taken at a certain point in time, the glucose tolerance test involves repeated testing to determine the rate at which glucose is processed by the body.

While the above tests are all taken from veinous blood, by constrast the arterial blood gas test is, as its name would suggest, taken from arterial blood, and is therefore more dangerous and uncomforable.

Large organic molecules

proteins

• Protein electrophoresis (general technique -- not a specific test)
• Western blot (general technique -- not a specific test)
• Liver function tests

Antibody proteins

• Serology (general technique -- not a specific test)
  • Wassermann test (for syphilis)
• ELISA test
• Coombs test

Other

• Polymerase chain reaction (DNA). DNA testing is today possible with even very small quantities of blood: this is commonly used in forensic science, but is now also part of the diagnostic process of many disorders.
• Northern blot (RNA)

Cells

• Full blood count (or "complete blood count")
• Hematocrit and MCV ("mean corpuscular volume")
• Erythrocyte sedimentation rate (ESR)
• Cross-matching. Determination of blood type for blood transfusion or transplants
• Blood cultures are commonly taken if infection is suspected. Positive cultures and resulting sensitivity results are often useful in guiding medical treatment.

External links

• Cold autoantibody webpage on "health a to z"

See also

• Reference ranges for common blood tests (with a much longer list)
• Urine test
• HIV test (uses several different techniques, including ELISA test and Western blot)
• Blood film
• Hematology
• Microbiologyhe:בדיקת דם

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