Serum phosphorus

Alternative names:

HPO4-2; inorganic phosphate; phosphorus - serum; PO4

What the risks are:

• excessive bleeding
• fainting or feeling lightheaded
• hematoma (blood accumulating under the skin)
• infection (a slight risk any time the skin is broken)
• multiple punctures to locate veins

Special considerations:

Antacids can bind PO4 and decrease absorption.

Nonpharmacological factors that can affect PO4 measurements include enemas containing sodium phosphate, excess vitamin D supplements, intravenous glucose administration (because PO4 enters cells along with glucose).

Drugs that can increase PO4 measurements include laxatives containing Na2HPO4 (sodium phosphate), methicillin and excess vitamin D or 1,25-dihydroxy vitamin D .

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.