Summary

DOI: 10.1373/clinchem.2016.261024

A critical value for total calcium was reported on a 68-year-old female patient who was admitted to the emergency department 15 h prior. The patient’s laboratory results were significant for a serum total calcium of 16.8 (8.4 –10.3) mg/dL, which was verified by replicate analysis, and her free calcium concentration of 2.25 (1.12–1.32) mmol/L. The patient’s serum phosphate was low at 0.5 (2.7– 4.5) mg/dL, and her parathyroid hormone (PTH)2 was also suppressed at 6 (15– 65) pg/mL.


Student Discussion

Student Discussion Document (pdf)

Terra A. Cederroth, Gary L. Horowitz, and Nicole V. Tolan*

Department of Pathology and Laboratory Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
*Address correspondence to this author at: Beth Israel Deaconess Medical Center, 330 Brookline Ave., Boston, MA, 02215. Fax 617-667-4533; e-mail [email protected].

Case Description

A critical value for total calcium was reported on a 68-year-old female patient who was admitted to the emergency department 15 h prior. The patient’s laboratory results were significant for a serum total calcium of 16.8 (8.4 –10.3) mg/dL, which was verified by replicate analysis, and her free calcium concentration of 2.25 (1.12–1.32) mmol/L. The patient’s serum phosphate was low at 0.5 (2.7– 4.5) mg/dL, and her parathyroid hormone (PTH)2 was also suppressed at 6 (15– 65) pg/mL. A review of the patient’s medical records revealed a past medical history significant for hypertension, hyperlipidemia, and non–insulin-dependent diabetes mellitus. Her medication list included aspirin (81 mg daily), pravastatin (80 mg daily), and verapamil (120 mg daily).

Questions to Consider

  • What is the differential diagnosis for increased calcium concentrations and what other laboratory tests should be considered?
  • What are the clinical symptoms of hypercalcemia?
  • What are the common preanalytic and analytic confounders to reporting accurate calcium concentrations?
  • In what conditions might it be therapeutic to intentionally increase a patient’s calcium concentration?

Final Publication and Comments

The final published version with discussion and comments from the experts appears in the February 2017 issue of Clinical Chemistry, approximately 3-4 weeks after the Student Discussion is posted.

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DOI: 10.1373/clinchem.2016.261024
Copyright © 2017 American Association for Clinical Chemistry