Phosphorus tests are most often ordered along with other tests, such as those for calcium, parathyroid hormone (PTH), and/or vitamin D, to help diagnose and/or monitor treatment of various conditions that cause calcium and phosphorus imbalances.
While phosphorus tests are most commonly performed on blood samples, phosphorus is sometimes measured in urine samples to monitor its elimination by the kidneys.
Since mildly abnormal phosphorus levels usually cause no symptoms, phosphorus testing is typically performed in follow up to an abnormal calcium test and/or when symptoms of abnormal calcium such as fatigue, muscle weakness, cramping, or bone problems are present.
Phosphorus testing may also be ordered along with other tests when symptoms suggest kidney and gastrointestinal disorders.
When conditions causing abnormal phosphorus and/or calcium levels are found, testing for both may be ordered at regular intervals to monitor treatment effectiveness.
Abnormally high levels of phosphorus can lead to organ damage due to calcification, deposits of calcium phosphate in the tissues. This is rare, however, and it is more common that high phosphorus levels lead to cardiovascular disease or osteoporosis.
Phosphate levels are normally higher in children than in adults because their bones are actively growing. Low phosphate levels in children can inhibit bone growth and high levels may be an indication of a condition that disrupts the body's balance of minerals.
Soft drinks and pre-packaged food items are high in phosphorus content, which some nutritionists believe contributes to over-consumption of phosphorus.
Blood and urine levels of phosphorus may be affected by the use of enemas and laxatives containing sodium phosphate, excess dietary vitamin D supplements, and by intravenous glucose administration.
This article was last reviewed on December 12, 2013. | This article was last modified on December 12, 2013.
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