Fasting Required: Yes 10-12 Hours Specimen: Blood Results: 2-3 Business Days Description: Phosphorus comes into the body through the diet. It is found in many foods and is readily absorbed by the intestines. A wide variety of foods, such as beans, peas and nuts, cereals, dairy products, eggs, beef, chicken, and fish, contain significant amounts of phosphorus. About 70% to 80% of the body's phosphates are combined with calcium to help form bones and teeth, about 10% are found in muscle, and about 1% is in nerve tissue. The rest is found within cells throughout the body, where it is mainly used to store energy. Methodology: Spectrophotometry (SP) Clinical Significance: Serum phosphorus (Phosphate) levels alone are of limited diagnostic value and should be correlated with serum calcium levels. An increased phosphorus with decreased calcium suggests either hypoparathyroidism or renal disease. A decreased phosphorus and an increased calcium suggests hyperparathyroidism or sarcoidosis. When both calcium and phosphorus are decreased diagnostic considerations include malabsorption, vitamin D deficiency and renal tubular acidosis. Increased phosphorus and normal or increased calcium suggests Milk-alkali syndrome or hypervitaminosis D.