Frequently Asked Questions

  • Can my laboratory enroll in a program at any time or do we have to wait until the beginning of the year to enroll?
    You can enroll at any time by completing our registration form. We will send you sample(s) for the next round.
  • Does the program ship proficiency testing samples to international locations?
    Yes, we ship PT test samples worldwide.
  • What are the costs associated with participation in the PT program?
    There is no cost for participation in the PT program. Participants are expected to analyze duplicate 50 g portions at their own expense and report results to OTSC via the web portal.
  • How are results submitted?
    Results are submitted through the results reporting portal on our website.
  • Which analytes does the PT Program support?
    Each round, there will the opportunity to test two samples – each containing either naturally occurring aflatoxin or fumonisin.
  • What methods/ test kits are acceptable for testing?
    The participating laboratories can use any method of choice. The chosen method must be provided with the results. Eligible methods include, but are not limited to, traditional instrument analysis (HPLC) and testing kit methods. The data analysis for results obtained by different methods will be reported in three categories: 1) testing kits, 2) other methods, and 3) all methods combined.
  • When do we need to submit results by?
    Check our website for sample submission and mailing dates.
  • Can we only participate in one round of the PT program?
    With the exception of One Sample Strategy firms in Texas, you will need to participate in both rounds of the program to receive a certificate.
  • Are there any customs restrictions to shipping samples?
    Please check with your country’s custom officials. In general, we have not had problems when shipping samples internationally.
  • Which labs are eligible for a certificate of participation?
    To receive a “Certification of Proficiency”, you will need to submit results for both rounds of the chosen analyte and your results must have a |z|-score < 2 on each of the two rounds. If you do not meet the criteria outlined above, but need documentation of participation, please contact us at See "About the Program" page for more information.
  • What happens if the lab misses the submission deadline?
    Please contact the program coordinator at
  • Our results are reported incorrectly. What should we do?
    Prior to the final report being released, please e-mail and we will reset your results and then you can enter the corrected results. After release of the final report, you can calculate your own z-score (see “Z-score Calculator”) The final report will not be altered once it has been published on our website

For any other questions, contact the program coordinator at

2024 Program

2024 Program Dates

Round 1 (Aflatoxin, Fumonisin & DON)
  • Samples mailed: February 15, 2024
  • Results Due: May 17, 2024 (Revised)
  • Reports Due: May 30, 2024 (Revised)