Dear Bio-Rad Customer,
In 2003, ISO published two international standards, EN ISO 17511 and EN ISO 18153 1. These
ISO standards are voluntary and represent an endorsement of two corresponding European
standards mandated to support the European In Vitro Diagnostic Directive that set requirements
for values assigned by diagnostic manufacturers to calibrators and control materials. Briefly,
these standards require that values determined for calibrators and controls be traceable to a
reference measurement procedure or reference material of higher metrological order (e.g. SI
units).
This letter is meant to inform you that both ISO and EN standards for traceability requirements
apply only to control materials that are intended to assess “trueness of measurement”. Such
controls typically have values assigned by a reference method. Daily use controls, such as
those manufactured by Bio-Rad, are intended to monitor analytical variation on a day-to-day
basis and are specifically exempted from the EN ISO requirements for traceability. The
exemption is found in the Scope of the ISO and EN standards and is worded as follows :
“This European Standard is not applicable to:
…control materials intended for intralaboratory quality control purposes and supplied with
intervals of suggested acceptable values, each interval obtained by interlaboratory consensus
with respect to one specified measurement procedure, and with limiting values that are not
metrologically traceable….”
Since all kit and instrument manufacturers as of December 7, 2003 must establish traceability for
their calibrators, any value for a sample (control material or human sample) derived using such
calibrators then becomes traceable according to the traceability chain associated with the specific
set of calibrators used. Any laboratory that requires specific information on the traceability chain
or the uncertainty of measurement surrounding the derived value, should contact the
manufacturer of the calibrator directly.
Sincerely,
Greg Cooper
Manager, Clinical Standards and Practices
Bio-Rad Laboratories
Quality System Division
9500 Jeronimo Road
Irvine CA 92618
USA
1
EN ISO 17511:2003(E) In vitro diagnostic medical devices-Measurement of quantities in
biological samples-Metrological traceability of values assigned to calibrators and control materials
EN ISO 18153:2003(E) In vitro diagnostic medical devices –Measurement of quantities in
biological samples – Metrological traceability of values for catalytic concentration of enzymes
assigned to calibrators and control materials