TNI Logo The NELAC Institute

Standard Interpretation



Standard: 2009 TNI
Section: V1M4, Section 1.7.3.2.2


REQUEST:

The Standard states: "The LCS shall be analyzed at a minimum of one (1) per preparation batch. Exceptions would be for those analytes for which no spiking solutions are available, such as TSS, TDS, TVS, TS, pH, color, odor, temperature, dissolved oxygen or turbidity." However, there are now spiking solutions available for some of these analytes such as TSS, TDS, TS, and many labs are using them. The Standard has not been updated to reflect the availability of these solutions, and this exception has been in effect since at least the 2001 NELAC Standard.

Are labs now required by the Standard to analyze an LCS for TSS, TDS, and TS since spiking solutions are now available? Is this section being changed in the 2015 Standard?

TNI FINAL RESPONSE:

A Laboratory Control sample is defined in the definitions as a sample matrix, free from the analytes of interest, spiked with verified known amounts of analytes or a material containing known and verified amounts of analytes and taken through all sample preparation and analytical steps of the procedure unless otherwise noted in a reference method. It is generally used to establish intra-laboratory or analyst specific precision and bias or to assess the performance of all or a portion of the measurement system.

Volume 1 Module 4 Section 1.7.3.2.2 of the standard states that "Exceptions would be for those analytes for which no spiking solutions are available.� If spiking solutions are now available then an LCS would be required per the standard. The quoted section of the standard is the exception. The examples listed are not an inclusive list and should be expected to change overtime therefore cannot be used as the exception but just as potential examples from the time in which the standard was written.

In addition Volume 1 Module 4 Section 1.7.3.2.3 of the standard states, "Alternatively, the LCS may consist of a media containing known and verified concentrations of analytes or as Certified Reference Material (CRM)."