Definition

Hypophosphatemia is a low level of phosphorus (phosphate) in the blood.

Alternative Names

Low blood phosphate; Phosphate - low; Hyperparathyroidism - low phosphate

Causes

The following may cause hypophosphatemia:

• Alcoholism
• Antacids
• Certain medicines, including insulin, acetazolamide, foscarnet, imatinib, intravenous iron, niacin, pentamidine, sorafenib, and tenofovir
• Fanconi syndrome
• Fat malabsorption in the gastrointestinal tract
• Hyperparathyroidism (overactive parathyroid gland)
• Starvation
• Too little vitamin D

Symptoms

Symptoms may include:

• Bone pain
• Confusion
• Muscle weakness
• Seizures

Exams and Tests

Your health care provider will examine you.

The following tests may be done:

• Kidney function tests
• Parathyroid hormone level
• Vitamin D blood test

Exam and testing may show:

• Anemia due to too many red blood cells being destroyed (hemolytic anemia)
• Heart muscle damage (cardiomyopathy)

Treatment

Treatment depends on the cause. Phosphate can be given by mouth or through a vein (IV).

Outlook (Prognosis)

How well you do depends on what has caused the condition.

When to Contact a Medical Professional

Contact your provider if you have muscle weakness or confusion.

References

Chonchol M, Smogorzewski MJ, Stubbs, JR, Yu ASL. Disorders of calcium, magnesium, and phosphate balance. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector's The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 18.

Klemm KM, Klein MJ, Zhang Y. Biochemical markers of bone metabolism. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 16.

Yu ASL. Diseases of magnesium and phosphorus. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 105.