Proficiency Testing

PT samples have to be right. Your laboratory’s accreditation is at stake, so anything less than 100% confidence is just not good enough.

That’s why we bring 20 years of multidisciplinary reference material manufacturing and certification experience into every step of our process. And that’s why our analytical validation specifications are more stringent than the current NELAC standards.

We start by certifying the purity of analyte source materials and then correcting sample assigned values for this certified purity. This correction increases the certainty of the assigned value.

We document the accuracy of each formulation and the homogeneity of each batch by instrumental analyses of each analyte in each of nine samples taken from the production run. No sample is ever released into a PT study unless the results of this analytical process meet our acceptance limits, limits more stringent by 30% than the current NELAC standards.

We close the PT study by documenting the stability of every analyte in every sample. This is your assurance that the sample was still right when your lab analyzed it.

Exceptional Value with Zero Defects

Sure this QA process is intensive, but it works. In the 10 years since PT privatization:
  • We have never issued a PT report to a customer or accrediting agency containing inaccurately entered, reported, or assigned values. 
  • We have never released a PT sample into a study with an inaccurate assigned value. 
  • We have never issued a broad-based amendment of PT reports due to previously unidentified sample problems.
That’s our track record, and we provide this performance at an exceptional value. All NPW and WS chemistry PT samples are always supplied in duplicate for prices comparable to other industry providers’ single-sample pricing.