Frequently Asked Questions

The intent of the following questions is to provide assistance to our guests who may be new to accreditation & proficiency testing and to those who wish to know more about NAPT. While we had hoped to address all the questions that you may have we know that is not possible, in the event your questions is not asked here please feel free to contact us with your question. We would love to hear from you.

All of us at NAPT are sure that once you have all the facts, your choice for a proficiency testing provider will be NAPT.

How quick can I receive an artifact?

The average wait for an ILC/PT is 2 to 4 weeks; although, there are several ILC/PTs that are scheduled out 2 to 4 months.  Please contact NAPT for ILC/PT availabilities.

Can you forward my reports to my AB?

Yes, NAPT will forward a copy of your final report to your accrediting body provided we have specific request to do so and are provided with the contact name and email address of the appropriate recipient.

Will my accreditation body accept your reports?

NAPT reports are recognized and accepted by all the leading accreditation bodies.

What are reference values?

The reference value is a value used to compare your results against. In any proficiency test, the results are only as good as the established values assigned.

NAPT's process for establishing the reference value was designed with the help of lead statisticians in the metrology community plus technical oversight by statisticians at NIST. Using standard technical practices, an analysis is performed and an appropriate reference value is assigned to the data set. We ensure that reference values and their associated uncertainties assigned are stable and worthy of being compared against.

Pivot and reference labs are accredited helping to ensure credibility of reference labs. To further analyze the results we also perform the following statistical reviews: Two Sigma, Three Sigma, Chauvnet Criterion, Sample Median, Trimmed Mean, Interquartile, Q-Test, and Thompson Technique. This is done in all cases to assure sound and meaningful results are published. During the course of each proficiency test, comprehensive technical reviews are conducted before, during, and after a kit is put into distribution. This is done to assure test integrity, establish and/or validate reference data and check for trends and/or anomalies in the data. NAPT's statistical review process is so robust that many of our advisors feel we have gone overboard in the analysis. It is their opinion that our technical review is unmatched by any ILC Provider.

These requirements are described in NAPT Quality Procedure 304-1 Data and Statistical Analysis Procedure. Only after a careful review of the data does NAPT assign an established reference value. To prematurely assign a reference value could be inaccurate and may result in a value that would not pass a robust analysis. Doing so would not ensure confidence in the reference value assigned. Making an assumption that a single measurement is the correct measurement, is not a technically sound process for ensuring the validity of the data. (No single laboratory is infallible.) That is why only after a thorough review of all data, should a reference value be assigned.

Do your technical advisors have access to my results?

No, the technical advisors assigned to a proficiency test do not have access to client data. The technical advisors are given raw data only. We know that one of the most important factors in designing meaningful proficiency tests is the involvement of technical advisors. One of the strengths behind NAPT’s success is the technical experts that assist us on a daily basis. The technical advisor is an expert in the field for which they provide assistance in.

Is NAPT accredited?

NAPT is an ISO/IEC 17043 accredited provider. NAPT Is the only proficiency test provider that can meet all of your needs via our offerings of proficiency tests. You can review our scope of accreditation on this site.

We are very proud of our accreditation, but we believe there is more to being a first-class proficiency testing provider then just been accredited.  Service, number & quality of value added proficiency tests are just a few examples of why NAPT is the clear choice when selecting a PT provider. We would ask you to compare the services that NAPT offers against other providers and after comparing everything we have to offer, you will see there really is no comparison.

What are the benefits of Membership?

Members receive:

  • ILC/PT Membership Discounts 
  • Automatic enrollment in NAPT’s Appreciation Program earn points towards free ILC/PT participations
  • Access to Technical Expertise of our Technical Director & technical expertise of NAPT's vast cadre of Technical Advisors
  • Listing on NAPT’s Website with a link to your website
  • Annual Membership Certificates showing your support of NAPT

What are the costs to participate?

NAPT's Fee Schedule is posted under Services.   NAPT believes you deserve real value for your participation and it is important to choose a trusted proficiency testing provider that will insure you receive real value for your participation.

Is the Membership fee annual or one time?

The membership fee is billed annually and covers a full calendar year.  Many benefits are included with a membership, See "What are the benefits of Membership?" 

Why did I pass my preliminary report but fail my final report?

Your results will depend, in large part, upon the reference value assigned to the artifact(s) contained in the ILC/PT.  See “What are reference values?” question above for how NAPT obtains its reference values.  Since ILC/PTs are in constant circulation, it is necessary to periodically ensure that reference values have not changed.  In the case where an artifact is recalibrated and the reference value has been found to have changed, participant data is reviewed to identify when the drift occurred.  If the drift is found to have occurred before your preliminary report was issued, your results will then be compared to the newly established reference values.  This may lead to a pass on your preliminary report, but a failure on your final report.

NAPT strives to minimize the impact of drift by selecting quality artifacts, scheduling regular pivot checks and monitoring data submitted by participants for any sudden changes in measurement data.