Foliage and Litterfall Ringtest and QA/QC information

The Needle and Leaf Interlaboratory Comparison Test programme runs every year. The normal procedure is:

• Informing the possible participating labs and NFCs (every year - e.g. 2021, 2022, 2023, ...)
• Registration of the participants via internet (until July)
• Distribution of the test samples and the invoice (July-August)
• Data submission by the labs (August-December)
• Deadline of data submission (end of December)
• Results (January - next year)
• Re-qualification process finished (September - next year)
• Re-qualification confirmed - successful participation in next ringtest

When a lab did not qualify and did not make efforts to improve the data quality, the PCC will send a letter to the respective  National Focal Centre informing it that the data may not be used for evaluations at European level.

The ringtest is financed by a participation fee, advertising and the preparation of ringtest samples by the participants.

• Instructions for ringtest sample preparation

Please, keep in mind that the submission of the monitoring results to the PCC database is only possible if your lab participated in the ringtest for all submitted parameters. If you want to participate and you need a labcode or/and password - please, contact Michael Tatzber.

• Web interface for registration and data submission
• Evaluation procedure
• Parameters and evaluation limits
• Excel file for requalification
• Last requalification status

Ringtest reports

27th Needle and Leaf Interlaboratory Comparison Test 2024/2025

26th Needle and Leaf Interlaboratory Comparison Test 2023/2024 - (Requalification Results) 

25th Needle and Leaf Interlaboratory Comparison Test 2022/2023

24th Needle and Leaf Interlaboratory Comparison Test 2021/2022

23rd Needle and Leaf Interlaboratory Comparison Test 2020/2021

22nd Needle and Leaf Interlaboratory Comparison Test 2019/2020

21st Needle and Leaf Interlaboratory Comparison Test 2018/2019

20th Needle and Leaf Interlaboratory Comparison Test 2017/2018

19th Needle and Leaf Interlaboratory Comparison Test 2016/2017

18th Needle and Leaf Interlaboratory Comparison Test 2015/2016

17th Needle and Leaf Interlaboratory Comparison Test 2014/2015

16th Needle and Leaf Interlaboratory Comparison Test 2013/2014

15th Needle and Leaf Interlaboratory Comparison Test 2012/2013

14th Needle and Leaf Interlaboratory Comparison Test 2011/2012

13th Needle and Leaf Interlaboratory Comparison Test 2010/2011

12th Needle and Leaf Interlaboratory Comparison Test 2009/2010

11th Needle and Leaf Interlaboratory Comparison Test 2008/2009

10th Needle and Leaf Interlaboratory Comparison Test 2007/2008

9th Needle and Leaf Interlaboratory Comparison Test 2006/2007

8th Needle and Leaf Interlaboratory Comparison Test 2005/2006

7th Needle and Leaf Interlaboratory Comparison Test 2004/2005

6th Needle and Leaf Interlaboratory Comparison Test 2003/2004

5th Needle and Leaf Interlaboratory Comparison Test 2001/2002

4th Needle and Leaf Interlaboratory Comparison Test 1999/2000

3rd Needle and Leaf Interlaboratory Comparison Test 1997/1998

2nd Needle and Leaf Interlaboratory Comparison Test 1995/1996

1st Needle and Leaf Interlaboratory Comparison Test 1993/1994

Additional documents and Excel sheets

Review of possible quality checks and other forms of assistance (Version 1, May 2008)

Excel file with instruction and example of control chart use

Internal Quality Control (Nordtest TR569)

Reference material for method validation