Understanding the Serum Angiotensin Converting Enzyme Test

Space-filling models of angiotensin I (left) and II (right).

Space-filling models of angiotensin I (left) and II (right). (Wikimedia Image)

Serum angiotensin converting enzyme test is a test that measures the amount of angiotensin converting enzyme in blood levels. Angiotensin converting enzyme is an enzyme that converts angiotensin I to angiotensin II. These two proteins play a vital role in regulating blood pressure. Angiotensin I is usually inactive, but when acted upon by angiotensin converting enzyme, it becomes angiotensin II.

Angiotensin II is the active form of angiotensin I. Angiotensin II causes the blood vessels to narrow. When there is a decrease in area, fluids (in this case, blood), flows faster, causing a resultant increase in blood pressure. Serum angiotensin converting enzyme test is primarily carried out to test for suspected cases of sarcoidosis, a disease that results in the formation of structures called granulomas in various organs. Granulomas are abnormal aggregations of inflammatory cells that, in some organs, form nodules.

Sarcoidosis may occur in an individual for years without any symptoms. When an organ is affected by sarcoidoisis, several symptoms may appear. These include weight loss, fatigue, arthritis and dry eyes. Skin symptoms may include rashes and lesions particularly on the face, neck and ears. The lymph nodes near the affected area may exhibit swelling (lymphadenophaty).

Sarcoidosis may also cause other symptoms depending on the area where it is located. When sarcoidosis affects the lungs, there would be lessening of the lungs air intake as well as blockages when severity increases. Sarcoidosis is usually asymptomatic, thus it is usually accidentally detected when undertaking mundane tests like x-rays, blood tests, CT scans of the chest area and lung biopsy.

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High angiotensin converting enzyme levels are a sign of sarcoidosis. An individual afflicted with sarcoidosis would have elevated levels of angiotensin converting enzyme. This could be 50% to 80% more than normal. Serum angiotensin levels are also related to the severity of sarcoidosis; rise and fall of the levels signify intensity or improvement of the condition.

Testing for serum angiotensin converting levels requires obtaining blood from the patient. Normal test results would be from 8 to 27 U/ml (units per milliliter). Individuals below the age of twenty have naturally high serum angiotensin converting enzyme levels, which may mask the presence of sarcoidosis.

There are several causes if a serum angiotenesin converting enzyme test results show low level of the enzyme. Low levels of angiotensin converting enzyme may be caused by hypothyroidism, a disorder that signifies a decrease in thyroid production. This disorder is primarily caused by iodine deficiency though other factors like radioactivity, genetics and environment may contribute to the development of the disorder.

Low levels of serum angiotensin converting enzyme may also be caused by the eating disorder anorexia nervosa. Anorexia nervosa is a disorder that generally manifests as a loss of any desire to consume food.

The disorders mentioned above can be very serious. They may escape the notice of several other tests. Undergoing a serum angiotensin converting enzyme test lets one know the possible occurrence of these disorders. This would better help him to take the appropriate steps to facilitate treatment and return to a healthy life.[ad#afterpost]

References

  • James, William D.; Berger, Timothy G.; et al. (2006). Andrews’ Diseases of the Skin: clinical Dermatology. Saunders Elsevier.
  • McGonagle D, McDermott MF (2006) A proposed classification of the immunological diseases. PLoS Med
  • White, E.S.; Lynch Jp, 3rd (2007). Current and emerging strategies for the management of sarcoidosis. Expert Opinion on Pharmacotherapy
  • Kumar MS, Safa AM, Deodhar SD, Schumacher OP (1977). The relationship of thyroid-stimulating hormone (TSH), thyroxine (T4), and triiodothyronine (T3) in primary thyroid failure.  American Journal of Clinical Pathology