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Conference Sessions Biomedical Metrology: Back to Basics of Test and Measurements

  • Date/Time September 30, 2022 8:30am - 10:00am
  • Room Bondi
  • Presenters David Heiselt and Donald Sheppard
  • CEU Credits 1.5


Participants will learn metrology terminology, definitions and calculations. They will be able to use these tools to aid them in reading and understanding equipment specifications and identifying the appropriate equipment for the test and measurements performed during Preventive Maintenance. Some of the key terms and their uses will include; Accuracy, Readability/Resolution, Scale, Uncertainty, TUR, TER, to name a few.

The participants will leave with a clear understanding of what to look for from manufacturer specifications to select the proper equipment as well as contributors that may affect the measurements during their testing and how to document these when necessary. Our goal is to give them more confidence to know they are performing the testing in accordance with manufacturer and regulatory guidelines.

Session Abstract

Measurement Basics for Biomedical Applications at Hospitals
“Back to the Basics of Measurement”
– Metrology – Science of Measurement
o Comparing a known measurement reference of higher accuracy to an unknown device/instrument
 Examples: Thermometer vs Boiling Water (100degC / 212degF)
• But How Do You Know?
o Water Quality
o Ambient Temperature / Pressure
o Surface Area Contact / Pot Construction
o Thermometer Accuracy
 Meter Accuracy
 Probe Accuracy
o Resolution vs Accuracy vs Precision Charts
– Definitions/Terminology
o Calibration vs P.M.
o Performance Test
o Test Reports and Certificates of Calibration
o Adjustment
o Uncertainty
o Traceability
o Etc
– Example Calibration vs Measurement Traceability
o SPO2
– Quality of Measurement
o How does a measurement not mean what it says
 True Value vs Indicated Value
 Measurement Uncertainty (common contributors)
• Manufacturer Specification
• Calibration Uncertainty from Service Provider
• Environment
• Measurement Noise (Resolution)
• Process Errors
• User Errors
 Paperwork From the Calibration shows the traceability of measurement
• When someone says NIST Traceable – they mean that the paperwork for the measurement chain can be traced to NIST
• ISO 17025 Accredited labs trace their measurements to the International Standard (otherwise known as the “S.I.” for the measurement at each reported test point.
o NIST is one piece of the S.I. measurement chain
o Routine Calibration Provides a Level Of Confidence to perform to specifications for service interval
 NASA’s Metrology and Calibration Program classifies the most common causes of Out-of-Tolerance conditions as:
• Inherent Nature of the Device (drift, mechanical wear, aging)
• Usage (environmental effects, mistakes in processes/procedures, user error or negligence)
• Transportation (shipping and handling problems)
– Payers/Purchasers vs Service Providers and Effects on Biomedical Applications
o How do the different players impact the patients, physicians and researchers effected by measurement
 Payers and Purchasers roles: Cost Avoidance/Reduction and setting up the service contract
• Cost vs Quality vs Service
 Service Providers: Measurement Accuracy and quality control for the items that do not meet specification. Secondary role as trainers and technical experts for the test equipment – can help diagnose equipment errors in setups.
 If the payers and purchasers choose the wrong service provider, they may not understand the applications and usage for equipment, resulting in faulty measurements during usage
 Bad measurements transfer from the Biomedical Department to the patient floor – bad patient monitoring can translate to misdiagnosis or death
o Calibration Reference: “NIST TRACEABLE” (which is not a standard) vs ANSI Z540, ISO 9001, ISO 10012, ISO 13485, ISO 17025, ANSI or ASTM, AS9100
 Which standard is right for you
 Which standard will give you more information
 ANSI Z540-1, ISO 9001, ISO 10012
• Basic Calibration Program with a functional quality program
 AS9100
• Aerospace Qualification for enhanced calibration and repair capabilities
 ISO 13484
• Medical Device Manufacturing Requirements
 ISO 17025, Z540.3 Accredited laboratories
• Accredited Calibration Program with detailed quality system, measurement uncertainty, and risk analysis.
• Required to participate in proficiency testing programs to maintain accreditation
o Comparison of measurement devices with other national partner laboratories
– Test, Measurement and Diagnostic Equipment Application Partnership
o Choose the measurement laboratory that understands your applications
 General Purpose Calibration Laboratory vs Specialized Calibration Services
• General Purpose Laboratory test to equipment specifications
o Wide capability of calibration.
o Can support and calibrate a vast majority of test equipment.
o General Equipment Knowledge
• Specialized Calibration Laboratory within specific industries
o Smaller/Focused Scope of Services
o Test items per application and customer requirements
o Technical Support and Training Capabilities
o Verify the services provided
 Audit the services provided by your calibration laboratory
 3rd Party Audit of Calibration Paperwork
• Accreditation Bodies such as ANAB, NIST, and A2LA have quality consultants that can review your calibration certificates for accuracy, proper calibration standards for the measurements, and uncertainty analysis.
o Practical Application Demonstration

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