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                                                                                                 Originally Published IVDT March 2006
  COMMENTARY


  An international effort to achieve comparability of test results
  Craig M. Jackson, Robert I. Wielgosz, and Willie E. May


  Globalization trends are spreading through the IVD industry just as in other
  industries. One major difference, however, is that while consumer product
  producers are largely unregulated, manufacturers of health-related
  products are subject to numerous regulatory requirements.
  Professionals from laboratory medicine companies, the IVD industry, and
  chemical metrology organizations have come together to address these
  regulatory challenges as well as the effects of globalization on medical
  product manufacturing and the needs of laboratories for quality and
                                                                                    L to R: Craig M. Jackson, PhD, is quality system
  uniform testing results. The Joint Committee for Traceability in Laboratory     procedures team leader of JCTLM Working Group
  Medicine (JCTLM) has been formed to aid laboratories, patients, and                1 and is president and cofounder of Hemosaga
  physicians in this pursuit by providing services to IVD manufacturers and      Diagnostics Corp. (San Diego). Robert I. Wielgosz,
  regulators. Descriptions of JCTLM and an example of traceability have                   PhD, is JCTLM secretariat and head of the
                                                                                 chemistry section of the Bureau International des
  been presented in previous issues of IVD Technology.1­4                         Poids et Mèsures (Sèvres, France). Willie E. May,
                                                                                      PhD, is cochair of JCTLM Working Group 1 and
  The traceability of diagnostic test results is a requirement of the European     director of the Chemical Science and Technology
  Union's Directive 98/79/EC on In Vitro Diagnostic Medical Devices (IVD          Laboratory at the National Institute of Standards
  Directive). Annex 1, section 3, of the Directive states the following:             and Technology (NIST; Gaithersburg, MD). The
                                                                                   authors can be reached at cjackso2@san.rr.com,
  The traceability of values assigned to calibrators and/or control materials        rwielgosz@bipm.org, and willie.may@nist.gov,
  must be assured through available reference measurement procedures                                                   respectively.
  and/or available reference materials of a higher order.5
  The term higher order is not defined in this directive, nor is a mechanism for meeting the regulation provided. Hence, the
  necessity for an organization to help fill this gap.
  JCTLM is committed to the goal of creating comparability of laboratory diagnostic test results by advancing the adoption of
  common worldwide reference systems. A critical step in reaching this goal is to ensure the traceability of diagnostic test
  values to a universally recognized and accepted reference point such as the international system of units (SI). JCTLM is
  addressing this issue by providing lists of higher-order reference materials and reference measurement procedures to which
  traceability can be established.
  Finding Common Ground
                   Metrological traceability to a common system of units provides the links among different levels of
   Sidebar:        measurement results, from the highest level (which is commonly impractical and too expensive for routine
   Traceability    use) to kit calibrators used for patient sample testing in the clinical lab. Because different measurement
   Online
                   procedures are often differentially influenced by the chemical and physical properties of the sample matrix,
                   traceability alone does not ensure equivalence of measurement results. However, many technical challenges
  to achieving measurement comparability are difficult to address until traceability has been established. For this reason alone,
  the efforts of the organizations participating in JCTLM are of great importance.
  JCTLM does not produce reference materials, nor does it develop reference measurement procedures. Rather, the
  committee was charged by its founders with establishing a process for identifying and reviewing the higher-order reference
  materials and reference measurement procedures required by the IVD Directive against agreed-upon criteria. Working group
  1 (WG1) was established to meet this obligation and maintain a published list of certified reference materials and procedures.
  A second team, working group 2 (WG2), has set up a reference laboratory network that provides outside calibration services
  to those needing to assign traceable values to calibrator and control materials.
  To accomplish its tasks, JCTLM, through WG1, solicits nominations for its database from national and international
  organizations. These groups provide reference materials, develop reference measurement procedures, or provide calibration

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Medical Devicelink                                                                                                        Page 2 of 3
  services as part of their charters or as a professional service to their members. In a few cases, the producers and providers
  are independent commercial entities. The database currently contains approximately 200 different materials for more than
  140 different measurands (analytes), and 125 reference measurement procedures for approximately 75 health-status
  markers.
  Using expert volunteers from professional societies, accreditation organizations, IVD manufacturers, and national metrology
  institutes, JCTLM teams review the submitted nominations against the requirements of the relevant ISO standards. As far as
  is possible, each review team is represented by manufacturers and groups from the United States, Europe, and the Asia-
  Pacific region. Membership on expert review teams is voluntary and individuals willing to participate are encouraged to apply
  or be nominated to serve on the review teams. The expectations of reviewers and the application form are available at
  JCTLM's Web site (see sidebar).
  Since its founding, JCTLM has committed itself to ensuring that its activities be transparent to all stakeholders. Thus, the
  review process occurs according to written procedures that together make up the JCTLM WG1 quality system. In particular,
  as part of the organization's philosophy of continuous improvement, the quality system undergoes continuous review and
  revision. This commitment is formalized in WG1 Procedure 7.
  Unfortunately, materials that fulfill the criteria of ISO 15194, a standard that describes reference materials, may not behave
  the same as patient samples in different measurement procedures. Likewise, procedures for a substance that fulfills the
  criteria of the ISO 15193, which describes reference measurement procedures, may yield somewhat different results. JCTLM
  is addressing this discrepancy by promoting comparisons of reference materials and reference measurement procedures.
  Procedures 4a and 4b of the WG1 quality system have been designed to address this issue. Reassuringly concordant, albeit
  limited, results from example studies performed at the National Institute of Standards and Technology (Gaithersburg, MD)--
  the U.S. national metrology organization--are included in the cited WG1 procedure documents.
  A Call to Action
  A new appeal for nominations for certified reference materials and reference measurement methods has been issued. All
  forms and instructions for nominating are available from the JCTLM Web site. Formally, nominations are received by the
  JCTLM secretariat, then transferred to WG1, whose chairs distribute the nominations to the appropriate review teams.
  Reviews are performed by the expert review teams according to WG1 Procedures 3, 4a, or 4b.
  The need for identifying new reference materials and reference measurement procedures is pressing. The rapid development
  of new health and disease markers provides clear evidence of this. In any given issue of the journal Clinical Chemistry, new
  and extremely useful laboratory procedures are presented; however, the results of these, depending upon method and
  manufacturer, often provide different values for the same substance.
  When the need for reference materials for new markers cannot be met with currently available materials, IVD manufacturers
  should communicate with organizations that produce such materials (for example, their national metrology institutes).
  JCTLM, through WG2, will soon identify and, via accreditation through other organizations, validate a list of reference
  measurement service providers for customers that require product traceability. These labs are academic, government, and
  commercial organizations that provide calibration and value-assignment services for IVD manufacturers' external quality-
  assessment programs. The results from the measurement services of these laboratories will be traceable to the entries on the
  JCTLM lists of materials and measurement procedures. The first list of reference measurement services is expected to
  appear in the latter half of 2006. After that, the list will be reviewed and updated annually.
  To demonstrate their competence and be listed by JCTLM, reference measurement service providers must participate in
  interlaboratory comparison studies. Measurement results from the studies also provide the data needed to verify equivalence
  of results obtained using JCTLM-listed materials and measurement procedures.
  Conclusion
  JCTLM has been working to meet the need for obtaining comparability and equivalence of measurement results throughout
  the world. JCTLM's international reach, along with the active participation of experts from professional societies, the IVD
  industry, and international and national accreditation groups, has enabled the organization to take a leading role in meeting
  these comparability goals. Although the founding of JCTLM was prompted by the European IVD Directive, its benefits far
  exceed simply providing lists to meet regulations. The transparency of its operations and its broad and open participation can
  be expected to make it successful where other organizations with similar goals have faltered.
  Acknowledgment
  The authors wish to thank Donna Kimball at the National Institute of Standards and Technology (NIST; Gaithersburg, MD) for
  producing the original documents from which this commentary was developed. JCTLM WG1 review team leaders were
  responsible for the processes embodied in the WG1 quality system.

  References

  1. DM Powers, "Coming Together on Traceability," IVD Technology 8, no. 6 (2002): 22­30.

  2. R Miller, "Metrological Traceability Requirements under the IVD Directive," IVD Technology 9, no. 7 (2003): 23­31.

  3. R Miller, "Recent Progress in Metrological Traceability," IVD Technology 12, no. 1 (2006): 22­27.



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Medical Devicelink                                                                                                                                  Page 3 of 3
  4. D Sogin, "Calibration of an immunochemical Assay for a New Biological Marker," IVD Technology 11, no. 7 (2005): 51­57.

  5. "Council Directive 98/79/EC of the European Parliament and of the Council of 27 October 1998 on In Vitro Diagnostic Medical Devices," Official Journal of
  the European Union L331 (December 12, 1998).


  Copyright ©2006 IVD Technology
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