Proficiency testing programs are operated by a third party, non-profit association. Participation in a proficiency testing program is a valuable improvement tool for Harris Laboratory. Two key proficiency testing programs that Harris Laboratory participates are:

North American Proficiency Testing (NAPT)
Greenhouse and Nursery Media Analysis Proficiency (GNMAP)

North American Proficiency Testing Program:
This group submits reference samples to Harris Laboratory on a quarterly bases for analysis. Laboratory results from the participating laboratory are then compared with data from all of the participating laboratories. Statistics are then determined so that laboratory data can be compared. The NAPT submits soil, plant, and irrigation water samples.

Greenhouse and Nursery Media Analysis Proficiency
The function and operation of this proficiency program is similar to the NAPT program. The same objectives are met. The GNMAP program submits soil-less potting media and nutrient solutions for analysis.

Participation in the NAPT and GNMAP program gives a Harris Laboratory insight into the measurement processes that translates into improved performance and enhanced measurement quality. The NAPT and GNMAP provides professional administration of interlaboratory comparisons/proficiency tests and round robins. All programs are conducted in accordance with current quality guidelines and standards. NAPT and GNMAP test results are accepted by all recognized accreditation bodies as being technically sound and in conformance with required standards.