Metrology inMetabolic Measurements    Wireless Health 2012          Jon K. Moon         MEI Research, Ltd
Metabolic Energy Balance23-10-2012            Wireless Health 2012
Measuring Energy Metabolism        • Direct measures             – Respiratory gas exchange             – Stable isotope e...
Respiratory gas exchange23-10-2012            Wireless Health 2012
Stable isotope exchange              (doubly labeled water – DLW)23-10-2012              Wireless Health 2012
Physiologic and motion sensors         Heart Rate                            Activity23-10-2012              Wireless Heal...
Defined Activity Patterns                                             Heart Rate23-10-2012            Wireless Health 2012
Measuring Energy Expenditure                      Room        DLW           Metabolic   Portable Physiologic              ...
Measuring Energy Expenditure                      Room        DLW           Metabolic   Portable Physiologic              ...
Validation is not Calibration• Compare to another system23-10-2012              Wireless Health 2012
Validation• Check against representative source of  measurand23-10-2012          Wireless Health 2012
Validation23-10-2012     Wireless Health 2012
Validation is not Calibration   But calibration alone isn’t the           solution either
Quality System                  Standards         Training             Traceability                      Records          ...
Adopt Quality System• Create calibration process      – Identify and obtain standards      – Develop calibration procedure...
ISO/IEC 17025:2005                 General Requirements for the Competence of                     Testing and Calibration ...
Quality System                   Standards Training              Traceability                    Records                Re...
Metrology23-10-2012    Wireless Health 2012
Metrology for Calibration• Metrology is the ‘science’ of measurements.  We apply it to develop calibration techniques.1. D...
Creating Calibration• Methods calibrate all measurement points in  the “device under test” (DuT)• 4:1 accuracy (measuremen...
Respiratory exchange calibration with   piston prover and pure gas blender23-10-2012       Wireless Health 2012
Multi-axis Acceleration Calibrators             Rate Table                          Positioner23-10-2012                Wi...
Wilbur Olin Atwater             and the Calorimeter at Wesleyan23-10-2012              Wireless Health 2012
Quality System                            Standards                                              Training             Trac...
ISO/IEC 17025:2005                          Traceability (5.6)    • ISO Measurement Traceability 5.6.2.1             – “th...
Traceability Pathway for Respiratory Gas                             Exchange23-10-2012                 Wireless Health 2012
Why are only room calorimeters under a laboratory qualitysystem?• Large and expensive• Permanent• Users fully informed  on...
Why are only room calorimeters under a laboratoryquality system?• Calibration points  are obvious and  available• Instrume...
If theYou can calibrate a cart           manufacturer makes provision23-10-2012       Wireless Health 2012
We don’t truly calibrate metabolic       carts and portable devices, so• There is no assurance of accuracy that comes  fro...
Why don’t we calibrate?• Manufacturer’s don’t provide appropriate  means for traceable calibration – because no  one asked...
We could Calibrate• Introduce metrology and quality systems to  physiologic research• Provide recommendations on procedure...
Quality System                  Standards         Training             Traceability                      Records          ...
Jon K. Moon, PhD  MEI Research, Ltd  St Louis Park, MNjmoon@meinergy.com    Meinergy.com
Upcoming SlideShare
Loading in …5
×

2.3 - Metrology in Metabolic Measurements

606 views
448 views

Published on

Tuesday, October 23, 2012
Technical Session #2: Energy Expenditure

John Moon (MEI Research, US)

0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
606
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
16
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide
  • Topic is measurements, calibration and quality system. Will use metabolic energy expenditure to illustrate.
  • Mean measuring EE (not biochemistry)Why metabolic measurement?Long history, predates metrology and quality. Has shown the best and problems – we have forgotten or unlearned much. Is an important derived parameter from mobile devices.
  • ISO 17025 covers requirements for testing and calibration labs. This document specific for calibration labs…it has some good ideas and calibration method…good starting placeThe key points of the document are to properly train personnel involved in the calibration process, Design and test a procedure, For ISO, you need to design a procedure and get it reviewed…they do not dictate how you do it. Keep detailed documentation of processes, changes to the system, environmental conditions, personnel performing the testing and resultsMake sure you are getting where you want to be…if not documentation will help you figure out where you are going wrongDid a new person get hired and not properly trained, does equipment need maintenance, do procedures need to be examined and changed?
  • In calorimeter this is flow, gas analysis (including water vapor) and pressure (to ensure integrity of sample). For PA monitor this would include acceleration amplitude and frequency plus clock. 4:1 or better. In some cases 10:1 is recommended. Example, to support 2% accuracy claim need calibration instrumentation in the range of 0.5% individual accuracy. Derates in unbiased situation roughly as Pythagorean sum. In other words, your overall accuracy for DuT must be less than the worst of your calibration instruments.
  • Way to brings system to a primary standard is traceability. Traceability is the …“Property of a measurement results whereby the result can be related to a reference through a documented unbroken chain of calibrations...”that can be followed back to SI, standard unitsThere are two levels of traceable standardsPrimary standards are based on fundamental physical constants. An example is a piston prover which determines flow based on volume and timeSecondary standards are standards calibrated by another national metrology institute. Such as using a flow controller calibrated to a national standard and using the controller to calibrate a flow meter.
  • How to bring traceability to Calorimetery LabsWe need to make flow and gas concentrations traceable to SI by utilizing national metrology labs, including the National Institute of Standards and Technology in the United States, the National Metrology Institute of Japan, and VSL – the National Metrology Institute of the Netherlands. The can be done through a combination of transports standards and metrology labs. While the method trace back to SI may vary between labs, the result is the same. Some labs will skip the transport standard. Different options for transport standardsNIST - National Institute of Standards and TechnologyNMIJ – National Metrology Institute of Japan VSL - National Metrology Institute of the Netherlandshttp://www.bipm.org/en/practical_info/useful_links/nmi.htmlBIPM Bureau International de Poid et Mesures – ensures world wide unifromity of measurements and their traceability to international standards
  • 2.3 - Metrology in Metabolic Measurements

    1. 1. Metrology inMetabolic Measurements Wireless Health 2012 Jon K. Moon MEI Research, Ltd
    2. 2. Metabolic Energy Balance23-10-2012 Wireless Health 2012
    3. 3. Measuring Energy Metabolism • Direct measures – Respiratory gas exchange – Stable isotope exchange • Less direct (proxy) measures – Heart rate – Heat flux – Motion23-10-2012 Wireless Health 2012
    4. 4. Respiratory gas exchange23-10-2012 Wireless Health 2012
    5. 5. Stable isotope exchange (doubly labeled water – DLW)23-10-2012 Wireless Health 2012
    6. 6. Physiologic and motion sensors Heart Rate Activity23-10-2012 Wireless Health 2012
    7. 7. Defined Activity Patterns Heart Rate23-10-2012 Wireless Health 2012
    8. 8. Measuring Energy Expenditure Room DLW Metabolic Portable Physiologic Calorimeter Cart Gas Monitors System Repeatability 2% 6% 5 – 11% ≥ MC ? Accuracy 2 – 4% 4 – 20% 10 – 20% ? < MC Resolution 2 – 15 4400 1 1 1 (min) Quality ISO IAEA None None None System ISO Reference23-10-2012 Wireless Health 2012
    9. 9. Measuring Energy Expenditure Room DLW Metabolic Portable Physiologic Calorimeter Cart Gas Monitors System Repeatability 2% 6% 5 – 11% ≥ MC ? Accuracy 2 – 4% 4 – 20% 10 – 20% ? ≥ 7% Resolution 2 – 15 4400 1 1 1 (min) Quality ISO IAEA None None None System ISO Reference23-10-2012 Wireless Health 2012
    10. 10. Validation is not Calibration• Compare to another system23-10-2012 Wireless Health 2012
    11. 11. Validation• Check against representative source of measurand23-10-2012 Wireless Health 2012
    12. 12. Validation23-10-2012 Wireless Health 2012
    13. 13. Validation is not Calibration But calibration alone isn’t the solution either
    14. 14. Quality System Standards Training Traceability Records Reviews Methods Equipment23-10-2012 Wireless Health 2012
    15. 15. Adopt Quality System• Create calibration process – Identify and obtain standards – Develop calibration procedure and initial interval• Train users / operators• Maintain records• Regular audit and review of records for adjustments23-10-2012 Wireless Health 2012
    16. 16. ISO/IEC 17025:2005 General Requirements for the Competence of Testing and Calibration Laboratories• Management System • “document policies, systems, programmes, procedures and instructions to the extent necessary to assure the quality of the test and/or calibration results”• Technical Requirements – Personnel (5.2) Training – Test and Calibration Methods and Method Validation (5.4) – Equipment (5.5) – Assuring the Quality of Test and Calibration Results(5.9) – Reporting Results (5.10) Documentation – Review System23-10-2012 Wireless Health 2012
    17. 17. Quality System Standards Training Traceability Records Reviews Methods Equipment23-10-2012 Wireless Health 2012
    18. 18. Metrology23-10-2012 Wireless Health 2012
    19. 19. Metrology for Calibration• Metrology is the ‘science’ of measurements. We apply it to develop calibration techniques.1. Determine what components of a system need to be calibrated2. Identify standard that has better certainty than the unit under test3. Determine required calibration interval23-10-2012 Wireless Health 2012
    20. 20. Creating Calibration• Methods calibrate all measurement points in the “device under test” (DuT)• 4:1 accuracy (measurement uncertainty) ratio between calibration and DuT• Calibration instruments need traceability to accepted and available standard• Calibration instruments become DuT for certification23-10-2012 Wireless Health 2012
    21. 21. Respiratory exchange calibration with piston prover and pure gas blender23-10-2012 Wireless Health 2012
    22. 22. Multi-axis Acceleration Calibrators Rate Table Positioner23-10-2012 Wireless Health 2012
    23. 23. Wilbur Olin Atwater and the Calorimeter at Wesleyan23-10-2012 Wireless Health 2012
    24. 24. Quality System Standards Training Traceability Records Reviews Methods Equipment23-10-2012 Wireless Health 2012
    25. 25. ISO/IEC 17025:2005 Traceability (5.6) • ISO Measurement Traceability 5.6.2.1 – “the programme for calibration of equipment shall be designed and operated so as to ensure that calibrations and measurements made by the laboratory are traceable to the International System of Units (SI) (Système international dunités). ” – “establishes traceability of its own measurement standards and measuring instruments to the SI by means of an unbroken chain of calibrations or comparisons linking them to relevant primary stands of the SI units of measurement. The link to SI units may be achieved by reference to national measurement standards.23-10-2012 Wireless Health 2012
    26. 26. Traceability Pathway for Respiratory Gas Exchange23-10-2012 Wireless Health 2012
    27. 27. Why are only room calorimeters under a laboratory qualitysystem?• Large and expensive• Permanent• Users fully informed on design and details of operation• PI and key staff remain engaged and are responsible for performance23-10-2012 Wireless Health 2012
    28. 28. Why are only room calorimeters under a laboratoryquality system?• Calibration points are obvious and available• Instruments are treated well• Economy of scale for calibration and quality system23-10-2012 Wireless Health 2012
    29. 29. If theYou can calibrate a cart manufacturer makes provision23-10-2012 Wireless Health 2012
    30. 30. We don’t truly calibrate metabolic carts and portable devices, so• There is no assurance of accuracy that comes from proven calibration, maintenance, or operation• They can’t serve as reference methods to calibrate other devices• We should avoid pooling data between labs, devices or over time23-10-2012 Wireless Health 2012
    31. 31. Why don’t we calibrate?• Manufacturer’s don’t provide appropriate means for traceable calibration – because no one asked them• Users don’t have the time, $, knowledge or interest.23-10-2012 Wireless Health 2012
    32. 32. We could Calibrate• Introduce metrology and quality systems to physiologic research• Provide recommendations on procedures and standards• Make calibration instruments, services and expertise affordable and available• Establish expectations for peer review and project funding23-10-2012 Wireless Health 2012
    33. 33. Quality System Standards Training Traceability Records Reviews Methods Equipment23-10-2012 Wireless Health 2012
    34. 34. Jon K. Moon, PhD MEI Research, Ltd St Louis Park, MNjmoon@meinergy.com Meinergy.com

    ×