The Magruder program is a proficiency testing program for fertilizers. Each subscribing laboratory receives one or two samples each month. The samples contain varying levels of plant nutrients as well as trace metal contaminants.

Samples are analyzed for analytes and methods chosen by the participating laboratory. Methods and results are reported on the web via Lab Portal. Comprehensive statistical reports are prepared based on protocols from ISO 13528:2015 (Statistical methods for use in proficiency testing by interlaboratory comparison). The reports are made available on the web for participating laboratories to evaluate their performance in testing the various analytes. Laboratories are identified only by number. Laboratory identification and performance is kept in strict confidence.

Every laboratory should implement and maintain an active quality assurance program. The Magruder program can become an important part of your laboratory quality assurance. Interlaboratory proficiency testing is a well-recognized method to monitor laboratory performance and ensure quality results. Additionally, participation in proficiency testing programs is a requirement for ISO 17025 and other laboratory accreditation programs.

To join the Magruder program, fill out the Membership Application under Documents on the main menu and email it to the contact on the form.