phosphate (PO4) test, a blood test used to detect hyperphosphatemia and hypophosphatemia. Abnormal phosphate levels are associated with renal failure, acromegaly, hyperparathyroidism or hypoparathyroidism, liver disease, advanced lymphoma or myeloma, hemolytic anemia, hypercalcemia, chronic alcoholism, vitamin D deficiency, diabetic acidosis, hyperinsulinism, and sepsis, among other conditions.