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Effects of Blood Clots on Measurements of pH and Blood Gases in Critical Care Analyzers

D’Orazio, Paul PhD

Point of Care: The Journal of Near-Patient Testing & Technology: December 2011 - Volume 10 - Issue 4 - p 186–188
doi: 10.1097/POC.0b013e318238cb76
Original Articles

Even with careful attention to reduce preanalytical errors, clots in samples are a reality in point-of-care locations where whole blood testing is conducted. Cartridge-based systems for analysis of pH, blood gases, and related critical care analytes present a unique challenge because often no user-performed maintenance is possible should a clot be aspirated into the system. Engineering solutions may be in place to prevent large clots from entering the system; however, these mechanical mitigations may not be effective in preventing aspiration of micro clots into the cartridge fluidic or sensing systems. In this report, we demonstrate the possibility of introducing clinically significant errors for measurement of pH, partial pressure of carbon dioxide, and partial pressure of oxygen if a blood clot becomes lodged on the surface of the electrochemical sensors for these analytes. The results point to the need for a quality management system, including a mechanism for detection and removal of clots from the surfaces of sensors in real time to reduce the possibility of reporting erroneous sample results.

From the Instrumentation Laboratory, Bedford, MA.

Reprints: Paul D’Orazio PhD, Instrumentation Laboratory, 180 Hartwell Rd, Bedford, MA. E-mail:

The author declares no conflict of interest.

© 2011 Lippincott Williams & Wilkins, Inc.