Why get tested?
To evaluate the level of phosphorus in your blood and to aid in the diagnosis of conditions known to cause abnormally high or low levels

When to get tested?
As a follow-up to an abnormal calcium level, if you have a kidney disorder or uncontrolled diabetes, and if you are taking calcium or phosphate supplements

Sample required?
A blood sample drawn from a vein in your arm or a timed urine collection (usually a 24-hour sample)