Phosphate is the most common mineral in the body after calcium. The body contains approximately 700 g of phosphate. About 85% of the phosphate is found in the bones as calcium phosphate, and only approximately 1% of it circulates free in the blood.
Phosphate is used for energy production in cells, regulating the body’s acid-base balance and the functioning of muscles and nerves. Phosphate plays an important role in the formation of bones and teeth. The body regulates the amount of phosphate by regulating its absorption from the gut and secretion from the kidneys. Vitamin D regulates the absorption of phosphate from the gut, and parathormone (PTH) regulates the secretion of phosphate from the kidneys.
We get phosphate from food in its natural, organic form, and also phosphate in inorganic form. Natural phosphate is abundant in whole-grain products, dairy products, and fresh meat and fish. The inorganic form of phosphate comes from additives and preservative agents added to food. Phosphate from additives is absorbed by the body twice as effectively as natural (organic) phosphate. Additives that contain a lot of phosphate are typically found in processed meat, processed cheese, and meat products.
When should phosphate be measured?
Phosphate is most commonly measured when investigating diseases of the parathyroid gland, vitamin D metabolism disorder, diseases of the bones, and kidney function.
Phosphate should also be measured when the following symptoms occur, for example:
- Stomach pain
- Memory disorders
- Joint pain
- Muscle pain
- Loss of appetite
- Weight loss
What does a phosphate test measure?
The test measures the amount of free phosphate in the blood. It is important to note that only approximately 1% of the phosphate in the body is free in the blood.
How is the phosphate result interpreted?
Normally, the result is:
- Women: 0.85–1.50 mmol/l
- Men <50 years: 0.75–1.65 mmol/l
- Men >50 years: 0.75–1.35 mmol/
Please contact your physician or other healthcare professional if you suspect an illness or need help interpreting the results.
Read more about defining reference values.
What can cause elevated phosphate values?
High phosphate levels (hyperphosphataemia) and low calcium levels activate the production of parathormone, which activates the release of calcium and phosphorus from the bones, causing osteoporosis and accumulation of calcium in the veins and soft tissue. Kidney failure is the most common cause of hyperphosphataemia.
Elevated phosphate values can also occur in connection with the following conditions:
- Hypoparathyroidism (underactive parathyroid)
- Excessive intake of vitamin D
- Low calcium levels
- Low hormone production in the adrenal cortex (Addison’s disease)
- Excess secretion of growth hormone (acromegaly)
What can cause decreased phosphate values?
Low phosphate levels are found in connection with the following conditions:
- Absorption of phosphate from the gut is decreased due to vitamin D deficiency
- Hyperthyroidism (overactive thyroid)
- Malabsorption of nutrients (malnutrition)
- Phosphate can also be secreted at an above-normal rate in connection with diseases of the kidneys (damage to the renal tubules).
- Alcohol withdrawal
- Parenteral or enteral feeding
The most typical additional phosphate tests:
- Vitamin D deficiency is a problem for many Finns (1220 D-25)
- Parathormone (4560 fP-PTH)
SYNLAB test list: Phosphate, inorganic (fS-Pi)
Fineli: Ravintotekijä fosfori https://fineli.fi/fineli/fi/ravintotekijat/2223
Munuais- ja maksaliitto: Ruokavalio https://www.muma.fi/sairaudet/munuaiset/sairastuneen_arki/ruokavalio
Fasting is required
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