Case Reports Clinical Chemistry 2025 Exercise 4: Pseudohyponatremia: Manifestation of Indirect versus Direct Ion-Selective Electrode Measurements

Authors

Ashley N. Ogorek, PhD

Clarence W. Chan, MD, PhD

Department of Pathology

The University of Chicago

Chicago, Illinois

Primary Audience: Pathologists and Clinical Scientists
Secondary Audience: Residents, Laboratory Technologist/Scientist (Includes all sub-specialty areas), Students, Pathologist Assistants,  Laboratory Directors and Educators

Upon completion of this activity, you will be able to:

·       determine if laboratory results are suggestive of pseudohyponatremia;

·       explain the mechanism of pseudohyponatremia and associated calculations;

·       discuss the differences between direct and indirect ISE used to measure sodium concentration; and

·       identify the underlying cause of pseudohyponatremia and the options for next steps in clinical management.