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Hypercalcemia in Emergency Medicine Workup

  • Author: Thomas E Green, DO, MPH, FACOEP, FACEP; Chief Editor: Romesh Khardori, MD, PhD, FACP  more...
Updated: Jul 08, 2014

Laboratory Studies

When calcium levels are reported as abnormal, the first step is to measure the albumin level. The following is a common formula used in calculating a corrected calcium level[9] :

Corrected total calcium (mg/dL) = (measured total calcium mg/dL) + 0.8 (for every decrement in the serum albumin of 1 g/dL below the reference value [in many cases 4.1 g/dL]; subsequently, subtract 0.8 for every increment in the serum albumin of 1 g/dL above the reference value)

If the corrected serum calcium level still is not accurate, it is possible to measure the free calcium ion activity (ie, ionized calcium level).

Other nonspecific laboratory abnormalities commonly found in patients with hypercalcemia result from disordered renal function. Patients commonly have significant azotemia at presentation.

Hypercalcemia may produce ECG abnormalities related to altered trans-membrane potentials that affect conduction time. QT interval shortening is common, and, in some cases, the PR interval is prolonged. At very high levels, the QRS interval may lengthen, T waves may flatten or invert, and a variable degree of heart block may develop. Digoxin effects are amplified.

After a diagnosis of hypercalcemia is established, the next step is to determine the cause. Initial testing is directed at malignancy, hyperparathyroidism, and hyperthyroidism, the most common causes of hypercalcemia.

  • The measurement of circulating PTH in the serum is the most direct and sensitive measure of parathyroid gland function. A reference range is 2-6 mol/L. A nonsuppressed PTH level in the presence of hypercalcemia suggests a diagnosis of primary hyperparathyroidism. If the PTH level is suppressed in the face of an elevated calcium level, hyperparathyroidism is unlikely.
  • Parathyroid hormone-related peptide (PTHrP) is thought to mediate the hypercalcemia that develops with many malignancies. Assays to measure this peptide are available. [13]
  • Measurement of calcitriol is difficult but can be accomplished. This laboratory value is useful in diagnosing hypercalcemia secondary to a granulomatous disease such as sarcoidosis. It is often elevated in primary hyperparathyroidism.
  • Other electrolytes also may be disturbed in hypercalcemia. Serum phosphate levels tend to be low or normal in primary hyperparathyroidism and hypercalcemia of malignancy. Phospate levels are elevated in hypercalcemia secondary to vitamin D–related disorders or thyrotoxicosis. Serum chloride levels usually are higher than 102 mEq/L in hyperparathyroidism and less than this value in other forms of hypercalcemia.

Imaging Studies

No imaging studies definitively diagnose hypercalcemia. However, the chest radiograph may reveal malignancy or granulomatous disease.[4]

Consider hypercalcemia in patients with multiple nonspecific complaints and an associated lung mass.

If laboratory evidence of primary hyperparathyroidism is present, CT scan of the head, MRI, ultrasound, or nuclear parathyroid scans may be helpful. Preoperative diagnostic imaging is essential in patients with previous neck surgery.

Contributor Information and Disclosures

Thomas E Green, DO, MPH, FACOEP, FACEP Associate Dean for Clinical Affairs, Des Moines University College of Osteopathic Medicine; Attending Physician, Emergency Department, Emergency Practice Associates; Associate Professor of Emergency Medicine, Midwestern University, Chicago College of Osteopathic Medicine

Thomas E Green, DO, MPH, FACOEP, FACEP is a member of the following medical societies: American College of Emergency Physicians, American College of Osteopathic Emergency Physicians, American Association for Physician Leadership, American Osteopathic Association

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.

Jeffrey L Arnold, MD, FACEP Chairman, Department of Emergency Medicine, Santa Clara Valley Medical Center

Jeffrey L Arnold, MD, FACEP is a member of the following medical societies: American Academy of Emergency Medicine, American College of Physicians

Disclosure: Nothing to disclose.

Chief Editor

Romesh Khardori, MD, PhD, FACP Professor of Endocrinology, Director of Training Program, Division of Endocrinology, Diabetes and Metabolism, Strelitz Diabetes and Endocrine Disorders Institute, Department of Internal Medicine, Eastern Virginia Medical School

Romesh Khardori, MD, PhD, FACP is a member of the following medical societies: American Association of Clinical Endocrinologists, American College of Physicians, American Diabetes Association, Endocrine Society

Disclosure: Nothing to disclose.

Additional Contributors

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

Disclosure: Nothing to disclose.


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 and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

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