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Updated: Dec 20, 2025
Evaluation of a Point-of-Care Testing Analyzer for Measuring Peripheral Blood Leukocytes
Published on: March 22, 2022
The Impact of Undetected In Vitro Hemolysis or Sample Contamination on Patient Care and Outcomes in Point-of-Care
Matthew O'Hara1, Elizabeth G Wheatley1, Steven C Kazmierczak2
1Trinity Life Sciences, Waltham, MA (formerly Boston Strategic Partners, Inc. Boston, MA).
Background:
Point-of-care (POC) testing is an integral diagnostic component in clinical settings like the emergency department (ED). However, most POC testing devices are unable to detect endogenous interferents such as hemolysis, which typically occurs during sample collection and handling and can falsely increase measured potassium (pseudohyperkalemia), a phenomenon we hypothesized may significantly impact patient care.
Methods:
In this retrospective study, we evaluated 100 unique admissions to the Oregon Health & Science University ED, presenting with elevated potassium measured at the POC. To evaluate whether in vitro hemolysis had occurred, POC test results were compared to repeat testing of the original specimen, or other specimens tested within 90 minutes in the Core laboratory. Review of associated Electronic Health Records determined whether elevated potassium initially measured using the POC analyzer was real, or due to in vitro hemolysis or contamination, and whether pseudohyperkalemia impacted patient management or care.
Results:
Of the 100 admissions with hyperkalemia measured using a POC analyzer, 40% were found to have pseudohyperkalemia due to hemolysis or contamination. Of these 40 patients, 6 experienced repeated testing, and an additional 5 were noted to have altered patient management, specifically due to pseudohyperkalemia.
Conclusions:
This study demonstrates the incidence of in vitro hemolysis, which is unknown to the POC operator, is high in patients who show an elevated potassium as measured at the POC. Furthermore, in vitro hemolysis can significantly impact patient management, suggesting that minimizing the incidence of unrecognized hemolysis will benefit hospital efficiency, decrease waste, and improve patient care.
Insights
Point-of-care (POC) testing can lead to pseudohyperkalemia due to sample hemolysis. This condition, often undetected by POC devices, impacts patient management and requires careful consideration in emergency departments.
Area of Science:
- Clinical diagnostics
- Laboratory medicine
- Emergency medicine
Background:
- Point-of-care (POC) testing is crucial in emergency departments (EDs).
- POC devices often fail to detect hemolysis, a common issue during sample handling.
- Hemolysis can cause falsely elevated potassium levels (pseudohyperkalemia), potentially affecting patient care.
Purpose of the Study:
- To investigate the incidence of pseudohyperkalemia due to in vitro hemolysis in ED patients with elevated POC potassium.
- To determine if pseudohyperkalemia impacts patient management and care.
Main Methods:
- Retrospective study of 100 ED admissions with elevated POC potassium.
- Comparison of POC results with core laboratory testing of original or recent specimens.
- Review of Electronic Health Records to assess the cause of elevated potassium and its impact on patient management.
Main Results:
- 40% of patients with elevated POC potassium showed pseudohyperkalemia due to hemolysis or contamination.
- Of those with pseudohyperkalemia, 6 required repeat testing, and 5 experienced altered patient management.
- Unrecognized in vitro hemolysis is a significant factor in elevated POC potassium measurements.
Conclusions:
- In vitro hemolysis occurs frequently in patients with elevated POC potassium, often undetected by the operator.
- Pseudohyperkalemia can significantly alter patient management, highlighting the need for improved sample quality assessment.
- Minimizing unrecognized hemolysis can improve hospital efficiency, reduce waste, and enhance patient care.
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