ABSTRACT
Potassium, calcium, magnesium, and phosphate are all important ions in body fluids and all appear in significant amounts in the urine. Potassium was discovered in the very early part of the 19th century. Calcium has been recognized as an important component of bone for more than 100 years. Phosphate metabolism is of great interest, but urinary phosphate has not provided a basis for practical study in disease as an indicator of renal or bone disturbances. Potassium is a widespread element in the plant and animal world. Urine calcium tests have important advantages since they readily identify urines with either decreased or increased amounts of calcium. There are a number of conditions in which urine calcium may be altered, and thus this test has the potentiality of becoming a "routine" in many types of urine study.
