Reference materials are typically used to establish
or validate the traceability of a routine measurement
procedure to a value assigned to the material by a reference
measurement procedure of higher order. When a reference
material is intended to be measured by a routine clinical
method, commutability must be validated among all of
the routine methods for which the reference material
is intended for use. Commutability has been defined
as the equivalence of the mathematical relationships
between the results of different measurement procedures
for a reference material and for representative samples
from healthy and diseased individuals.1
This definition is based on the more technical definition
in ISO document 17511.2 Commutability does not imply
accuracy or trueness of results, only that results for
a reference material had the same mathematical relationship
between two methods that was observed for native clinical
samples measured by the same two methods.
Fresh frozen serum creatinine reference materials from the National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 967 and from the College of American Pathologists’ (CAP) Accuracy Calibration Verification/Linearity Survey LN24 were found to be commutable with a panel of native clinical serum samples for the manufacturers’ reagents and instruments listed below. Reference materials and clinical samples were measured by the stated analytical system and by a LC/IDMS reference measurement procedure at NIST. Commutability was evaluated using criteria described in Clinical and Laboratory Standards Institute (CLSI) document EP14-A2.3
Commutable Reagents and Instruments
| Manufacturer |
Reagent (Product Number) |
Instrument Model |
| Abbott Diagnostics |
Creatinine(7D64) |
Abbott ARCHITECT cSystemsTM c8000 |
| Abbott Diagnostics |
Creatinine (7D64) |
Abbott AEROSET® System Abbott Diagnostics Creatinine, Next Generation (3L81) Abbott ARCHITECT cSystemsTM c8000 |
| Abbott Diagnostics |
Creatinine, Next Generation (3L81) |
Abbott AEROSET® System |
| Siemens Diagnostics |
Creatinine_2 (B01-4126-01) |
ADVIA® 1650 Chemistry |
| Siemens Diagnostics |
Creatinine Enzymatic (B01-4127-01) |
ADVIA® 1650 Chemistry |
| Beckman Coulter, Inc. |
CREA (442760) |
Synchron® CX4 PRO |
| Beckman Coulter, Inc. |
CREA (442760) |
Synchron® Unicel DxC 800 |
| Beckman Coulter, Inc. |
Creatinine (443340) |
Synchron® CX3 Clinical System |
| Beckman Coulter, Inc. |
CREm (472525) |
Synchron® Unicel DxC 800 |
| Dade Behring, Inc. |
Dimension® CREA Flex (DF33A) |
Dimension® RxL System |
| Ortho Clinical Diagnostics |
CREA Slides (814 1947) |
VITROS® 950 Chemistry System |
| Olympus Diagnostics Systems |
Creatinine (OSR6178) |
Olympus AU400® |
| Olympus Diagnostics Systems |
Creatinine (OSR6178) |
Olympus AU640e® |
| Roche Diagnostic Corporation |
CREA plus (11775642) |
Hitachi 911 Analyzer |
| Roche Diagnostic Corporation |
CREA/RB (12217333) |
Hitachi 911 Analyzer |
The list provided here documents commutability of the NIST SRM 967 and CAP LN24 reference materials with native clinical serum samples for various reagent-instrument combinations determined for specific reagents used on these specific instrument systems and may not apply to different reagent-instrument combinations. However, since these reference materials met the CLSI EP14-A2 criteria for commutability with all reagent-instrument combinations tested, one would expect these reference materials to be commutable with native clinical serum samples when the same reagent is used on very similar instruments using the same methodological principle. Nevertheless, caution should be exercised in extrapolating the above findings to different reagent-instrument combinations, even when the instruments and reagents are all produced by the same IVD manufacturer. It is recommended that clinical laboratories consult with the manufacturer(s) of their reagent and instrument to determine the applicability of the established commutability characteristics for these reference materials to particular configurations of creatinine reagents and instrument systems.
References
- Miller WG, Myers GL, Rej R.
Why commutability matters. Clin Chem 2006;52:553-4.
- ISO International Standard
17511:2003(E). In vitro diagnostic medical devices
- Measurement of quantities in biological samples
- Metrological traceability of values assigned to
calibrators and control materials. First edition,
2003-08-15. International Organization for Standards,
Geneva, Switzerland, 2003.
- CLSI Document EP14-A2. Evaluation
of Matrix Effects; Approved Guideline – Second
Edition. Clinical and Laboratory Standards Institute,
Wayne, PA, USA, 2005.
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