Laboratory Studies

Serum phosphate level:

Serum phosphate or phosphorus normally ranges from 2.5-4.5 mg/dL in adults. Hypophosphatemia is defined as mild (2-2.5 mg/dL), moderate (1-2 mg/dL), or severe (< 1 mg/dL).
Since the serum phosphate level may not accurately reflect the level of intracellular phosphate, always correlate serum phosphate levels with clinical findings, especially before embarking upon aggressive replacement therapy.

Abnormalities in serum magnesium, calcium, and potassium levels may occur.

Hypomagnesemia often is associated with the shift of phosphate into cells.
Hypercalcemia is common in primary hyperparathyroidism.
Derangements in serum potassium may occur with certain hypophosphatemia causes, such as DKA and alcoholism.

Other Tests

Urine measurements of phosphate excretion, such as 24-hour excretion or fractional excretion of filtered phosphate, are usually not measured in the emergency department, but these tests may be helpful for admitted patients. These tests provide further evidence of renal versus extrarenal source.^[31]

An electrocardiogram should be obtained to assess for arrhythmia.

Treatment & Management

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Author

Alex Koyfman, MD Assistant Professor, Department of Emergency Medicine, University of Texas Southwestern Medical Center, Parkland Memorial Hospital

Alex Koyfman, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Coauthor(s)

Brit J Long, MD Associate Professor, Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences; Staff Physician, Department of Emergency Medicine, Associate Program Director - Research, San Antonio Uniformed Services Health Education Consortium

Brit J Long, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Howard A Bessen, MD Professor of Medicine, Department of Emergency Medicine, University of California, Los Angeles, David Geffen School of Medicine; Program Director, Harbor-UCLA Medical Center

Howard A Bessen, MD is a member of the following medical societies: American College of Emergency Physicians

Disclosure: Nothing to disclose.

Chief Editor

Erik D Schraga, MD Staff Physician, Department of Emergency Medicine, Mills-Peninsula Emergency Medical Associates

Disclosure: Nothing to disclose.

Additional Contributors

Robin R Hemphill, MD, MPH Associate Professor, Director, Quality and Safety, Department of Emergency Medicine, Emory University School of Medicine

Robin R Hemphill, MD, MPH is a member of the following medical societies: American College of Emergency Physicians, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Adam J Rosh, MD Assistant Professor, Program Director, Emergency Medicine Residency, Department of Emergency Medicine, Detroit Receiving Hospital, Wayne State University School of Medicine

Adam J Rosh, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Luda Khait, MD, MS Resident Physician, Department of Emergency Medicine, Detroit Medical Center, Detroit Receiving Hospital

Luda Khait, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, Michigan State Medical Society, Emergency Medicine Residents' Association

Disclosure: Nothing to disclose.

Acknowledgements

Devon J Moore, MD Resident Physician, Department of Emergency Medicine, Wayne State University Detroit Medical Center, Detroit Receiving Hospital

Devon J Moore, MD is a member of the following medical societies: American Medical Student Association/Foundation, Emergency Medicine Residents Association, and Wayne State School of Medicine Black Medical Association

Disclosure: Nothing to disclose.