TNI Logo The NELAC Institute

TNI Standards Guidance

Disclaimer: This material represents the opinion of its authors. It is intended solely as guidance and does not include any mandatory requirements except where such requirements are referenced. This guidance does not establish expectations of being implemented universally, exclusively, in whole, or in part.

This guidance does not establish or affect legal rights or obligations and is not finally determinative of the issues it addresses. It does not create any rights enforceable by any party in litigation with TNI, its accreditation bodies, or affiliated institutions. Any decisions made by TNI regarding requirements addressed in this guidance will be made by applying the applicable standards, policies or procedures to the relevant facts.


Module: Toxicity

Subject: Demonstration of Capability

Question 1

Is it acceptable to have an Initial Demonstration of Capability (IDOC) test count both towards the new organisms (from a new supplier, for instance) and a new analyst?  And, would a different salt matrix require a separate IDOC?  The premise of the question is that “stacking” a number of IDOCs onto the same test run could potentially save a lot of time and money.

A lab may use the vendor’s SRT to demonstrate organism health, but must have one IDOC for ongoing capability with the new organism source and a separate IDOC for the new analyst(s).

One SRT using organisms from the new vendor without any other new variables performed by an experienced analyst (that is, one qualified with a current acceptable DOC) is sufficient if the result is not different from historical lab-generated data (within the lab-established control limits).  If the result is different, the lab must establish a new IDOC separately by an experienced analyst to compare results with the new analyst(s) for their qualification.

The same is true for the different salt matrix.  If a new SRT test with no other new variables falls within the established control limits, there is no need for another IDOC.


NELAC 2003 Standard

Chapter 5, §, Demonstration of Capability
Chapter 5 Appendix C – Demonstration of Capability
Chapter 5, Appendix D2 §1.a.1)

2009 TNI V1M7 §1.6.2

1.6.2 Initial DOC
An initial DOC shall be made prior to using any method, and at any time there is a significant change in personnel or method or any time that a method has not been performed by the laboratory or analyst in a twelve (12) month period. The laboratory shall document each initial DOC in a manner such that the following information is available for each affected employee:
a)       analyst(s) involved in preparation and/or analysis;
b)       matrix;
c)       species and endpoint(s);
d)       identification of method(s) performed;
e)       identification of laboratory-specific SOP used for analysis, including revision number;
f)        date(s) of analysis;
g)       summary of analyses, including information outlined in Section If the method or regulation does not specify an initial DOC, the following procedure is acceptable. It is the responsibility of the laboratory to document that other approaches to initial DOC are adequate.
Each analyst shall meet the QC requirements as specified in Section