NIH.gov: Errors in Potassium Measurement: A Laboratory Perspective for the Clinician

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3662091/

Abstract

Errors in potassium measurement can cause pseudohyperkalemia, where serum potassium is falsely elevated. Usually, these are recognized either by the laboratory or the clinician. However, the same factors that cause pseudohyperkalemia can mask hypokalemia by pushing measured values into the reference interval. These cases require a high-index of suspicion by the clinician as they cannot be easily identified in the laboratory. This article discusses the causes and mechanisms of spuriously elevated potassium, and current recommendations to minimize those factors. "Reverse" pseudohyperkalemia and the role of correction factors are also discussed. Relevant articles were identified by a literature search performed on PubMed using the terms "pseudohyperkalemia," "reverse pseudohyperkalemia," "factitious hyperkalemia," "spurious hyperkalemia," and "masked hypokalemia."

Abstract

Errors in potassium measurement can cause pseudohyperkalemia, where serum potassium is falsely elevated. Usually, these are recognized either by the laboratory or the clinician. However, the same factors that cause pseudohyperkalemia can mask hypokalemia by pushing measured values into the reference interval. These cases require a high-index of suspicion by the clinician as they cannot be easily identified in the laboratory. This article discusses the causes and mechanisms of spuriously elevated potassium, and current recommendations to minimize those factors. "Reverse" pseudohyperkalemia and the role of correction factors are also discussed. Relevant articles were identified by a literature search performed on PubMed using the terms "pseudohyperkalemia," "reverse pseudohyperkalemia," "factitious hyperkalemia," "spurious hyperkalemia," and "masked hypokalemia."

Keywords: Factitious hyperkalemia, Hemolysis, Potassium, Pseudohyperkalemia, Reverse pseudohyperkalemia, Spurious hyperkalemia

Introduction

It has been estimated that 60-70% of clinical decisions are based on laboratory results and potassium is among the ten most commonly tested analytes.[1] About 4-32% of all laboratory errors occur during the analytical phase of testing the sample. The majority of errors (32-75%) occur before the sample is analyzed: During labeling, collection, transport or centrifugation.[2] The rest of the errors occur during report generation or interpretation. ...