Serum Phosphorus
Serum Phosphorus
- This test is meant to measure the level of phosphate in the blood
- No special preparation is required.
- This test would provide a value for phosphate compound in the blood
What is Serum Phosphate Test ?
Phosphorus is a mineral the body needs to build strong bones and teeth. It is also important for nerve signaling and muscle contraction.
This test is ordered to see how much phosphorus is in your blood. Kidney, liver, and certain bone diseases can cause abnormal phosphorus levels. Total body phosphorus in a 70-kg man is about 700 to 800 mg, 85% of which is in the skeleton in hydroxyapatite phase; the remaining 15% is in soft tissues.
Phosphorus is present in ample amounts in many foods (e.g., red meat, dairy products, legumes). An average diet contains about 1.0 to 1.5 g a day. The gastrointestinal (GI) tract absorbs 75 to 80% of the ingested phosphate, and the rest is excreted in the feces. Higher phosphate intakes lead to high absorption, but the percentage of GI absorption is about the same. Low phosphate intake results in more complete absorption.
Reported Parameters
Serum Phosphate Value
Normal values range from:
- Adults: 2.8 to 4.5 mg/dL
- Children: 4.0 to 7.0 mg/dL
Serum Phosphate is higher between 8 am – 11 am. So if the blood sample is taken in the morning, the value will be slightly higher than if the sample is taken later in the day.
All The Questions that you might have
- Why is Serum Phosphate test done ?
- How to interpret the results of this test ?
- At what time of the day this test should be conducted ?
- What are the normal values for Serum Phosphorus ?
Patients who are suffering from a renal disease tend to have higher or lower levels of phosphorus. Patients in the ICU are also subjected to this test to measure the levels of Serum Phosphorus.
Disorders of phosphate homeostasis occur in a wide range of clinical conditions. Both hyper- and hypophosphatemia can be caused by cellular shifts of phosphate. The three primary conditions that lead to phosphate dysfunction are dietary intake, GI, and renal status. Since serum inorganic phosphate is only a minute portion of body phosphate, alterations in the serum level can occur when the body phosphate is low, normal, or high.
A higher than normal level (hyperphosphatemia) may be due to many different health conditions. Common causes include:
- Diabetic ketoacidosis (life-threatening condition that may occur mainly in people with type 1 diabetes)
- Hypoparathyroidism (parathyroid glands do not make enough of their hormone)
- Kidney damage or failure
- Liver disease
- Too much vitamin D
- Too much phosphate in your diet
- Use of certain medicines such as laxatives that have phosphate in them
A lower than normal level (hypophosphatemia) may be due to:
- Alcoholism
- Hypercalcemia (too much calcium in the blood)
- Primary hyperparathyroidism (parathyroid glands make too much of their hormone)
- Too little dietary intake of phosphate
- Very poor nutrition
- Too little vitamin D, resulting in bone problems such as rickets (childhood) or osteomalacia (adult)
Serum phosphate should ideally be determined in the fasting state. A recent meal, high glucose ingestion, insulin release or administration, muscular activity, and hyperventilation can all lower serum phosphate by causing a shift from the plasma into the cells.
The normal serum phosphorus concentration is 2.8 to 4.5 mg/dl (1.12 to 1.45 mmol/L). This fluctuates with age (it is higher in children than adults), dietary intake, and acid–base status. There is a diurnal variation, which reaches its nadir between 8 and 11 a.m.
