Asian Soil Laboratory Network: 3rd meeting. Manila, Philippines, 23 - 27 September 2019. Mr. Wang Hong

1. Implementation of national PT for Soil
Testing in China
Dr. Wang Hong
Institute of Agricultural Resources and Regional Planning,
Chinese Academy of Agricultural Sciences
E-mail: wanghong01@caas.cn；gjhf@caas.cn
Tel: 86-10-82108648；86-10-82106196
Sep. 23-27, 2019 Manila, Philippines

2. The logo of qualification accreditation certification
consists of certificate number and the pattern which
that is the acronym of China Inspection Body and
Laboratory Mandatory Approval. Test reports bearing
the CMA mark are accepted as legal documents in China

3. Certification and Accreditation Administration of the People’s Republic of China
(CNCA) is established by the State Council and is authorized by the State Council to
exercise administrative responsibilities of undertaking unified management,
supervision and overall coordination of certification and accreditation activities
across the country.
Certification and Accreditation Administration of
the People’s Republic of China (CNCA)
Main Operation
•China Compulsory Certification
•Voluntary Product Certification
•Management System Certification
•Service Certification
•Accreditation work
reditation certification consists of certificate number and the pattern which that is the acronym of China Inspection Body and Laboratory Mandatory Approval. Please re

4. In March 2006, CNCA announced the “Measures for the
Implementation of Laboratory Capability Verification” to
establish a unified national capacity verification management
mechanism.
National project of proficiency testing for inspection
and testing capability verification work
A projects
The qualification certificate for inspection and testing institutions
issued by CMA must participate in it.
B projects
The proficiency testing project collected, reviewed and issued by the
Certification and Accreditation Administration encourages all types of
inspection and testing institutions to participate voluntarily.

5. China National Accreditation Service for Conformity Assessment
China implements a unified accreditation system in
accordance with international practice. China National
Accreditation Service for Conformity Assessment is the
national accreditation body established and authorized by
CNCA to take overall responsibility for the accreditation
on certification bodies, laboratories, inspection bodies and
other conformity assessment bodies under the provisions
of Regulations of the People’s Republic of China on
Certification and Accreditation.

6. CNAS is the member of International Accreditation Forum (IAF) and
International Laboratory Accreditatin Cooperation (ILAC), and has signed the
IAF Mutilateral Recognition Agreement (IAF MLA) and ILAC Mutual
Recognition Arrangement(ILAC MRA).
The accreditation certificates issued by CNAS, within IAF MLA scopes or ILAC
MRA scopes, towards laboratories, are also recognized by accreditation bodies
in other economies who have the same IAF MLA scopes or ILAC MRA scopes.
CNAS has Intenational Cooperation with MLA/MRA

7. Accredited Bodies

8. CNAS in accordance with the relevant international standards
and technical requirements for use, choice and operation ability

9. 1) CNAS shall require the testing laboratories to attend PT verification to prove
their ability.
2) CNAS set a rule to stipulate the minimum requirements for the testing
laboratories to participate in PT verification.
3) The testing laboratories should report to CNAS information on its participation
in PT verification as required.
PT POLICIES
The requirements of CNAS
Soil chemical analysis : one
times/item/2year

10. The flow chart showing the activities of PT (Inter-
laboratory comparisons)
http://www.eeaa.gov.eg/eimp/index.html

12. ISO 13528. Statistical methods for use in proficiency testing
by interlaboratory Comparisons
Homogeneity Test

13. Stability Test

14. Certified reference materials of soils in China
as the samples used for PT

15. Reference Material Producers
Certified reference materials of soils in China

17. National Institute of Metrology, China

18. China National standard reference materials :Soils

19. Certified Reference Material s(CRM)
for Available Nutrient of Agricultural Soils
Ten certified reference materials for soil available nutrients have been
introduced since 2010.

20. Reference Value
The reference values with
uncertainty at a stated level
of confidence were
measured by 13
laboratories.

21. CNAS-RL06:2018 Rules for the accreditation of
proficiency testing provider
Which laboratories or
companies could provide a
Proficiency test (PT) ?

22. ISO/IEC 17043:2010“Conformity assessment - General
requirements for proficiency testing”
Accreditation criteria for proficiency testing providers

23. Proficiency Testing Providers
ISO/IEC 17043:2010“Conformity assessment - General requirements
for proficiency testing”

24. China NIL Research Center for Proficiency
Testing (NIL for short hereafter) was
founded on December 23, 2002.
NIL was accredited by China National
Accreditation Service for Conformity
Assessment (No. CNAS PT0002) in
August 2003.
NIL carries out proficiency testing activities
in accordance with ISO/IEC 17043:2010
“Conformity assessment General
requirements for proficiency testing " to
evaluate the ability of testing laboratories
and monitors them continually.
China NIL Research Center for Proficiency Testing

26. Proficiency testing scheme

28. Our laboratory obtained a “satisfactory” result of
proficiency testing in soil total phosphorus in 2017

29. Problem：PT providers can not supply enough items of
agricultural soils to the testing laboratories

31. The three performance statistics most widely
used to evaluation of proficiency test results
The percent difference performance statistic is simply the difference between
a participating laboratory test data and the test artifact's assigned value,
divided by the test artifact’s assigned value, multiplied by 100.
Where x = participating laboratory test data, X = test artifact assigned value.

32. The z-score performance statistic takes the difference between a
participant’s test data and the test artifact’s assigned value divided by a
variability performance statistic such as standard deviation.
Where s = measure of variability.
The variability performance statistic used in the z-score computations should
be based on enough observation as to reduce the influence of extreme test
results.
The z-score performance statistic

33. The En number performance statistic is derived by dividing the
difference between a participating laboratory test data and the test
artifact’s assigned value by the square root of the sum of the squares
(RSS) of the participating laboratory test data uncertainty and the
independent laboratory’s test artifact’s assigned value uncertainty.
The En number performance statistic
Where U²lab = participant laboratory test data uncertainty,
U²ref = independent laboratory test artifact assigned value uncertainty.

34. The following are industry accepted values for evaluating Z-scores
and En numbers.
Z-scores
|z| ≤ 2 = satisfactory performance
2 < |z| < 3 = questionable performance
|z| ≥ 3 = unsatisfactory performance
En:
En ≤ 1 = satisfactory performance
En > 1 = unsatisfactory performance
if proficiency test performance results are satisfactory?

35. From 2007 to 2019, Ministry of Agriculture and Rural
Areas provided PT for the technical capability verification
of soil heavy metal detection in different laboratories

36. In China, PT is required by the offices of the
national laboratory qualification management to
evaluate the abilities of the testing laboratories.
CNAS has set series rules to manage PT
providers and PT Implementation mainly
according to ISO standards and guidelines.
Summary

37. Thanks for your attention