Frequently Asked Questions

This varies by matrix and method. Refer to past reports for past participation.

Yes – The customer decides the frequency and the analytes reported.

No. All subscriptions are offered on an annual basis only. However, customers may enroll midyear. For customers enrolling midyear, past test items from the current year will be shipped with the first shipment, as available. No guarantee is made that all test items will be available since they are produced consistent with enrollment at the time of production.

The shipping method is selected by the customer at the point of enrollment. The options include:

• USPS First Class – USA
• USPS First Class International parcel service.
• USPS Express Mail International.
• International customers only can also use a courier service (must provide account #).

This varies with the shipping method chosen. For example, with USPS Express Mail estimated shipping time of 3 to 5 business days and full tracking. AAFCO cannot guarantee nor estimate delivery times for international laboratories.

There may be issues with customs, this varies by country.

No. It is the responsibility of the customer to secure all needed import permits or certificates.

Homogeneity studies are performed periodically. In lieu of doing studies for each round, markers are monitored statistically.

Packaged materials are stable within the reporting time frame under ambient conditions.

Six Laboratories

Consensus values, Robust Standard Deviation and uncertainties, Z-Scores and method precision.

The robust procedures significantly down weights the outliers.

Z = (Lab_avg – Robust Mean)/Horwitz σ_ffp
For example:
Lab_avg = Laboratory Average = (Result₁ + Result₂)/2 = (3600 + 3700)/2 = 3650
Robust Mean = 2512
Horwitz σ_ffp = Horwitz predicted fit-for-purpose (ffp) standard deviation (σ) = 349.8
Z = (3650 – 2512)/349.8 = +3.25

The assigned value for Total Fumonisin is calculated from the values submitted for Total Fumonisins not the individual Fumonisins.

Robust statistics are used and described at https://pt-drw.aafco.org/CSPStatsDocs/CSPStatsDocs.html

The last day of the month following the Results Due Date.

Yes

No

Click here to learn more about PT / QRM failure investigations.

The material is added to the QRM once the report is released.

Animal Feed Scheme program materials can be found here.