Proficiency tests and interlaboratory comparisons

By participating in proficiency tests and interlaboratory comparisons, laboratories receive an independent assessment of their performance, can compare their results with those of other laboratories, and can ensure that their measurement results are accurate and reliable.
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Proftest Syke - provider of interlaboratory comparisons and proficiency tests

We provide a wide range of interlaboratory comparisons for different sectors, for example related to environmental measurements. As proficiency testing experts we offer our services as consultants and trainers and we develop our services continuously to fulfill the needs of the evolving field of analytics.

We provide proficiency testing services and expert support

We provide proficiency testing and interlaboratory comparison services for

  • chemical, physical and biological measurements of environmental samples, 
  • measurements of swimming pool and domestic waters,
  • calorific value measurement in solid fuels,
  • sampling and field measurements of environmental samples,
  • testing of recycled material,
  • indoor air measurements (VOC and PAH compounds), and 
  • asbestos analysis of building material samples.

We have provided expert support for proficiency tests provided by cooperation institutes.

Advisory group, Proftest Syke 2022 - 2027:

More information on interlaboratory comparisons

Interlaboratory comparisons (ILCs) are tests organized in the same way for two or more participants on the same or similar samples and of the predetermined variables. They are used to externally evaluate the performance of the participants and the comparability of the analytical results. Interlaboratory comparison is a proficiency test (PT) when the performance evaluation is done against predetermined criteria. Participation in interlaboratory comparisons provides external quality assessment of the routine analyses and the laboratories can compare their results with those from other participants.

Proftest Syke is a FINAS (Finnish Accreditation Services) accredited proficiency testing provider (ISO/IEC 17043) PT01 (FINAS).

Current proficiency tests and interlaboratory comparisons

Registration is open to proficiency tests and interlaboratory comparisons listed below. Contact us if you need any further information.

  • ProftestWEB is the electronic client interface of Proftest Syke. Via the interface you can e.g. register into a PT/ILC and report your results. If there are problems in using the interface or you need access to the interface, contact us.

    ProftestWEB

  • Guide for laboratories participating in Proftest Syke proficiency tests and interlaboratory comparisons:

    Proftest Syke, Guide for participants (pdf, 540.4 KB)
  • Once the samples of a certain scheme have been delivered, the scheme information will be removed from the list below (Registration is open). Ongoing schemes can be found in ProftestWEB. Additional information about registration (among other things) can be found in the Frequently Asked Questions at the bottom of this page. 

Registration is open for these PTs / ILCs:

Following PTs will open for registration in December 2025:
  • SPW 01/2026
  • NW 02/2026

Currently the registration is not open for any PT/ILC.

Annual program - Proficiency tests and interlaboratory comparisons

The proficiency tests and interlaboratory comparisons organized by Proftest Syke according to the annual plan can be found in the accordion boxes below, divided by themes. The information of a certain scheme will be removed from this page once the final report of the scheme has been published. The information for the entire year can be found in the downloadable annual program below. A preliminary long-term plan for the coming years (downloadable) can also be found below.

Detailed information about the proficiency tests and interlaboratory comparisons will be published approximately 1-2 months before the announced sample delivery or scheme implementation date. At that time, registration for the respective scheme will also open. Accreditation does not cover interlaboratory comparisons or determinations marked with an asterisk (*).

The annual program for 2027 will be published in October-November 2026, at which time it will be updated on this page.

Annual program 2026

Sustainable use of water resources

Natural water

  • Natural water analyses I 
    Test ID: NW 02/2026
    Sample Delivery: Week 8
    Measurands: Alkalinity, conductivity 25 °C, NH4-N, NO2-N+NO3-N, Ntot, PO4-P, Ptot, PO4-P dissolved, Ptot, dissolved, pH
  • Natural water analyses II 
    Test ID: NW 06/2026
    Sample delivery: Week 19
    Measurands: Chlorophyll a, oxygen, SiO2, TOC, TIC, salinity

Wastewater

  • Wastewater analyses I 
    Test ID: WW 03/2026
    Sample delivery: Week 12
    Measurands, wastewater: BOD7, CODCr, CODMn, Na, suspended solids, TOC
    Natural water: BOD7, CODMn
  • Wastewater analyses II 
    Test ID: WW 13/2026
    Sample delivery: Week 48
    Measurands: Alkalinity, conductivity 25 °C, colour, NH4-N, NO2-N+NO3-N, Ntot, PO4-P, Ptot, pH

Drinking water

  • Drinking water analyses 
    Test ID: DW 09/2026
    Sample delivery: Week 37
    Measurands: CODMn, F-, Cl-, conductivity, hardness, pH, NO2-, NO3-, NH4+, Fe, Mn, Ca, K, Mg, Na, SO42-
Built environment

Swimming pool water analyses 

  • Test ID: SPW 01/2026
    Sample delivery: Week 5
    Measurands: Combined, free, and total chlorine, KMnO4, NO3-, pH, turbidity, urea

Microbiological housing health analysis* 

  • Test ID: ASTE 04/2026
    Timing: April 2026
    Cultivation method, identification of pure cultures, 
    direct microscopy, direct cultivation, qPCR method
    Cooperation partner: Aerobiology Laboratory of the Biodiversity Unit of the University of Turku

Gross and net calorific values of solid fuels

  • Test ID: CAL 08/2026
    Sample delivery: Week 36
    Measurands: Gross and net calorific value, moisture and ash content, 
    volatile compounds, C, Cl, F, H, N, and S
    Cooperation partner: Eurofins Environment Testing Finland Oy, Jyväskylä

Identification and counting of man-made mineral fibres*

  • Test ID: MMMF 10/2026
    Timing: September-October 2026
    Cooperation partner: Aerobiology Laboratory of the Biodiversity Unit of the University of Turku

VOC measurements from indoor air samples* 

  • Test ID: IAVOC 11/2026
    Timing: October-November 2026
    TVOC and separate compounds according to the standard ISO 16000-6
    Cooperation partner: Finnish Institute of Occupational Health
Hazardous substances and Circular economy

Metals in water and sludge 

  • Test ID: MET 05/2026
    Sample delivery: Week 17
    Measurands: Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, 
    Mn, Mo, Ni, P, Pb, Sb, Se, Sn, Ti, V, Zn
    From sludge also: Drw, N

Leaching behaviour test for solid waste material

  • Test ID: LT 07/2026
    Two stage batch leaching test
    Sample delivery: Week 22
    Measurands: As, Ba, Cd, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Se, V, Zn, 
    Cl-, F-, SO42-, DOC, pH, conductivity, TDS

VOC measurements in water and soil 

  • VOC 12/2026
    Sample delivery: Week 47
    Measurands: Volatile organic compounds (VOC)
Sustainable use of water resources (2025)

Wastewater

  • Wastewater analyses II
    Test ID: WW 11/2025
    Sample delivery: Week 48
    Measurands: chloride, conductivity, colour, NNH4, NNO2+NO3, Ntot, PPO4, Ptot, pH, sulphate

Drinking water

  • Drinking water analyses
    Test ID: DW 07/2025
    Sample delivery: Week 37
    Analyses: Alkalinity, fluoride, chloride, conductivity, hardness, pH, NO2, NO3, NH4, Fe, Mn, Ca, K, Mg, Na, sulphate, TOC, turbidity

Intercomparison test for field measurements*

  • Test ID: KMV 08/2025
    Timing: September 2024
    Measurands: Conductivity, oxygen, pH, temperature, turbidity
    Place: Natural water body, Tampere
Built environment (2025)

Gross and net calorific values of solid fuels

  • Test ID: CAL 06/2025
    Sample delivery: Week 36
    Measurands: Gross and net calorific value, moisture and ash content, volatile compounds, C, H, N, S, Cl, F
    Cooperation partner: Eurofins Environment Testing Finland Oy, Jyväskylä

Asbestos in building materials samples*

  • Test ID: ABS 19/2025
    Sample delivery: Week 39
    Measurands: Analysis and identification of asbestos
    Cooperation partner: FIOH
Hazardous substances (2025)

Natural water and wastewater metal analyses

  • Test ID: MET 04/2025
    Sample delivery: Week 18
    Analyses: Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Se, Ti, V, Zn 

Oil hydrocarbons in water and soil 

  • Test ID: OIL 10/2025
    Sample delivery: Week 45
    Measurands: C5-C10, >C10-C40, >C10-C21, >C21-C40

Proficiency testing reports

Preliminary results reports

  • The preliminary results report of the proficiency tests and interlaboratory comparisons is delivered to the participants within 1-2 weeks after the reporting deadline of the participant results (for case-specific details see the information letter of the scheme). 

Final reports

  • The final report of the proficiency tests and interlaboratory comparisons is published within 2-6 months after the publication of the preliminary results report.
  • The final report is mainly published in Finnish when more than 90 % of the participants are from Finland (and it is not stated otherwise in the information letter of the scheme). Otherwise, the final report is published in English.
  • The final reports are published in the University of Helsinki open repository. In here we have listed direct links to the published reports.
Final reports, proficiency testing schemes 2025
Final reports, proficiency testing schemes 2024
Final reports, proficiency testing schemes 2023
Final reports, proficiency testing schemes 2022
Final reports, proficiency testing schemes 2006-2021

Direct links to the final reports older than those listed year-by-year above are complied into a separate document.

FAQ Frequently asked questions

We have compiled frequently asked questions related to Proftest Syke’s activities along with their answers here. The questions are divided into six topics. In case of a need, the easiest way to contact us is via email.

Registration and customer information

Where do I find information about your annual program?

  • Check out our annual program in section Proficiency tests and interlaboratory comparisons, annual program (earlier on this page). From the same section you can also find our long-term program (non-binding).

When can I register for a PT scheme?

  • Registration for the PT/ILC scheme is usually done through ProftestWEB, and registration typically opens 1–2 months before the sample dispatch date mentioned in the annual program (even earlier during the summer). If you are interested in a specific scheme, you can contact us. We will add your contact information to the distribution list for the scheme and send you the registration instructions when the registration for the scheme opens.

I forgot to register on time, could I still register?

  • Right after the deadline for registration, it is very likely that you can still register. If more time has passed, the possibility to register needs to be examined by us. In both cases, please contact us and we will send you further information.

There is conflicting information in the information or sample letter?

  • Please, contact us via email. We will solve the conflict and, when necessary, correct the letters, send them by email to participants and upload them to ProftestWEB.

May I cancel my registration?  

  • The registration is binding, but in exceptional cases the participant may cancel their registration free of charge no later than two weeks before the sample delivery date. After that the participant will be charged 70 % of the basic fee.

How do I inform changes in contact person or address?   

  • In contact person changes, please inform us. The address changes you can inform on the Customer information page on ProftestWEB.
ProftestWEB

I do not have a username for ProftestWEB.

  • If your laboratory has participated in our PTs, please contact us. We will give you a permission to use the client interface. If your laboratory has not yet participated in our PTs, you may register into a proficiency test without logging in. Select page Orders in ProftestWEB and fill up your contact and other information carefully while placing the order. The order is binding. When we process your order, you will get a permission to use the client interface.

My username on ProftestWEB doesn’t work?

  • If you have forgotten your password, you can reset your password via the Reset password link on ProftestWEB. Create then a new password via the link sent to your email.
    If the email for creating the password is not found, please also check the spam box.
    If there seems to be a problem with your web browser, please try to use ProftestWEB with another browser (Chrome, Firefox, Edge). 
    The web browser's firewall settings (workstation specific) can cause problems with the operation of ProftestWEB. We can’t influence these settings, please contact your own ICT support.
    The username for ProftestWEB is personal. If you don’t have a personal username, please contact us.

ProftestWEB neither reacts nor allows to continue.

  • If ProftestWEB is not used for a longer while (> 30 min), your session expires, and the system will log you out. The problem is solved by updating the page view of the web browser (ctrl + R or F5) and logging in again.
Samples

I haven’t received the samples, what should I do?

  • Please check the foreseen arrival date of the samples indicated in the information letter (check also the possible arrival time).
    If the sample package has not arrived as informed, please contact us.

Some samples are missing or broken, what I can do?

  • Please report the information and possible problems via the sample arrival form. A link to the form can be found in the sample letter.
    You can also contact us via email.

I would like to order more samples from the current round. What should I do?

  • If samples are still available, we can provide them. Please contact us. Sample prices and additional shipping costs will be added to the invoice.

Can I order samples from the previous tests?

  • It is possible to order samples from previous proficiency tests. Proftest SYKE stores the samples until the publication of the final report. The stable samples are kept for 2 years. The fee for such samples is the sample price and delivery costs. Please, contact us.
Results

Could I deliver the results after the reporting deadline? 

  • As the PT carefully follows the given timetable, the results cannot be accepted after the reporting deadline. In exceptional case, please contact us.

The result form is not found on ProftestWEB or it does not work.

  • For some PTs, the results are reported using for example an Excel file and then the result form in ProftestWEB is not in use. In these cases, on ProftestWEB, the result form is visible but cannot be edited (unfortunately, in those cases, it cannot be hidden).
    The web browser's firewall settings (workstation specific) can cause problems with the operation of ProftestWEB. We are unable to influence these settings, please contact your own ICT support.
    If the result form is not found on ProftestWEB or it does not work, please contact us. We will solve the situation out as soon as possible.

I'd like to report two sets of results. What should I do? 

  • Please contact us and we create a second order for you. For each additional data set we charge an additional fee of 40 % of the basic fee.

Can I correct my results? (Results are reported for example incorrectly or in a wrong unit) 

  • Reported results can be edited on ProftestWEB until the given reporting deadline. If there are any problems with the correction of the results, please contact us.  
    After the publication of the preliminary result report, the participant results will be corrected only if the organizer has interpreted the results incorrectly.  In the final report a written evaluation will be given for the corrected results. 

How is the z score calculated? 

  • Instructions to calculate the z score are provided in out Guide for participants, Appendix 3.
    In performance evaluation, the z score is calculated from the precise result reported by the participant. In the result sheet of the final report, the participant’s result might slightly differ from the reported value due to the number of visible decimals or due to rounding. Hence, the z score calculated manually using the data from the final report might differ from the reported z score.
Proftest Syke, Guide for participants (pdf, 540.4 KB)

Where do I find the participant code for a certain PT?

  • You can find your participant code via ProftestWEB: Log into the interface > Select Tests > Select Orders (on the left side bar). From the Orders table you can find the participant codes (Participant id column). 
    You can find your participant code via ProftestWEB also like this: Log into the interface > Select Tests > Select the test from the list > The code is in the Results table, in Participant id column.
Reports

When is the preliminary results report delivered?

  • The preliminary results report is delivered to the participants usually in two weeks after the reporting deadline of the participant results. The more precise publication timetable (week of publication) of the preliminary results report is informed for each scheme. After the publication, the preliminary results report is available on ProftestWEB, on the page of the test (some exceptions occur). The availability of the preliminary results report is informed via email to the contact person of the participant.
    The preliminary results report is confidential.

When will the final report be published?

  • The final report is published within 3-4 months after the sample delivery. The more precise publication timetable (month of publication) of the final report is informed for each scheme. After the publication, the final report is available via ProftestWEB as well as via the Proftest Syke website (section Proficiency test reports). All participants of the proficiency test will be informed of the published report via email.
Feedback

How can I give feedback?

  • Feedback and questions can be given via email.
    The feedback and question are collected for each PT and ILC and those are published with their replies in the final report. 
    Feedback can be given also via ProftestWEB.
    General feedback related to the Proftest Syke services could be sent directly to Tero Eklin, Director of research infrastructures (firstname.lastname@syke.fi).

More information

Proftest Syke

Published 16.1.2025 / Updated 27.11.2025