Interlaboratory comparison of the IAG - International Analytical Group, Section Feed Analysis

The IAG Ring Test is an international proficiency test that is performed once a year. The ring test comprises the following samples, which are tested for ingredients, additives and undesirable substances:

  • Roughage, unground - mostly alfalfa or green meal pellets (sample S1, 700 g).
  • Compound feed, unground - common commercial product, complete or supplementary feed (sample S2, 700 g)
  • Mixed feed, ground - mixed feed for special parameters (e.g. Hg, Cr, Ni, antioxidants, organic acids, ...), partially doped (sample S3, 300 g)
  • Mineral feed, unground - usual commercial product (sample S4, 400 g).

Additionally, airtight sealed, ground subsamples (approx. 40 g) of sample S1 and S2 are submitted for the determination of moisture in order to provide a statistical evaluation of this parameter.

S1 + S1a S2 + S2a S3 S4
Roughage, unground Mixed feed, unground Mixed feed, spiked with special parameters, ground Mineral feed, unground
Ingredients, digestible protein, fiber fractions (ADFom, NDFom, ADL, ELOS) Ingredients including starch & sugar, calculated energy - -
Elements and heavy metals Elements and heavy metals Ni, Cr and As, Cd, Hg, Pb, F (spiked) Elements and heavy metals

Amino acids, vitamins (A, E, D3) Phytase, coccidiostats

Antioxidants, organic acids (spiked), coccidiostats

Fat soluble Vitamins (A, E, D3), water soluble vitamins (B1, B2, B6, niacinamide, panthothenic acid), phytase, probiotics (Bacillus sp.)



Samples in the IAG 2024

The goal of the IAG round robin is to provide laboratories with opportunities to:

  • verify the accuracy of their results
  • verify the technical expertise of their staff
  • verify the functionality of their laboratory equipment
  • to fulfill the requirement of the accreditation bodies to participate in proficiency testing.

The organization and performance of proficiency testing is based on EN ISO 17043.


You can register here  until March 17, 2024 at the latest.

If you need further information please contact

Participation fee

€ 100,-/sample (excl. VAT) plus shipping costs

Additional sample material for internal quality assurance can be purchased for € 70 (excl. VAT) plus shipping costs, while stocks last.

Shipping costs:

  • Europe: € 30 for up to 4 samples, € 50 for more than 4 samples
  • Asia and USA: € 55 for up to 4 samples, € 90 for more than 4 samples
  • Australia and New Zealand: € 80 for up to 4 samples, € 130 for more than 4 samples
  • other countries on request

After payment of the participation fee and shipping costs the samples will be shipped in May 2024.

Scope of examination/methods

With the samples you will receive a letter with all relevant information and instructions. The results have to be entered in an EXCEL- template, which includes all the parameters to be examined (ingredients, mineral and trace elements, heavy metals, amino acids and depending on the feed also additives such as vitamins, enzymes, MHA, coccidiostats, antioxidants).

It is not mandatory to analyze all offered parameters. The methods of analysis are not mandatory, but should be indicated for better interpretability of the results (indication of the standard or by means of a code). The results obtained with NIRS are evaluated separately. The results are to be given as individual values (mean value of repetitions usual in the laboratory) related to dry matter. In addition, a cover letter with all relevant information and instructions is sent with the samples.

Statistical evaluation

The evaluation is anonymous and includes the determination of mean, median, standard deviation, coefficient of variation and z-score according to ISO 13528 by means of software R. The results report is available in electronic form. The results are confidential and may not be passed on or published without the consent of the IAG.

Results evaluation

Each participating laboratory will receive an overall report, a confirmation of participation, and an individual report documenting success (including the number of outliers).

Meeting for results discussion or summary report

Depending on requirements of the participating laboratories, the results of the proficiency test will be discussed in an (online) meeting or, alternatively, a summary of noticeable results and findings will be sent out to all participants in autumn 2024. Here, the participants have the opportunity to give feedback and to place wishes and suggestions for the next IAG PT.


Invitation: February 2024
Deadline for registration: March 15, 2024
Invoice dispatch: March/April 2024
Sampling: April 2024
Sample preparation and homogeneity test: April 2024
Dispatch of samples: May 2024
Analysis of sensitive parameters: June 24-28, 2024 (week 26)
Deadline for results submission: July 19, 2024
Discussion of results/ summary report: Autumn 2024


Dipl.-HTL-Ing. Gerhard Liftinger

Last updated: 15.05.2024

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