PTP Program

Diesel Exhaust Fluid

2024 Annual Fee:

Schedule: April, November
Sample amount distributed each test cycle: 2 Liter

Reduced Price

Register for Multiple Programs
A2LA Accredited Symbol

Accredited Proficiency Testing Provider*

This program is accredited in accordance with the recognized International Standard ISO/IEC 17043: 2010 Conformity Assessment - General Requirements for Proficiency Testing, by the American Association for Laboratory Accreditation. Certificate Number: 4209.01

List of Programs and Scopes

About The Program

ASTM’s Diesel Exhaust Fluid (DEF) Proficiency Testing Program provides laboratories with a statistical quality assurance (SQA) tool, enabling labs to compare, improve, and maintain a high level of performance in the use of ISO methods with other laboratories worldwide. Diesel Exhaust Fluid (DEF), as standardized in ISO 22241[1], is an Aqueous Urea Solution of with 32.5% high-purity urea (AUS 32) and 67.5% deionized water.

DEF is a consumable required by many modern diesel engine applications using selective catalytic reduction (SCR) technology to reduce oxides of nitrogen (NOx) exhaust. Impurities in the DEF can cause the SCR, which is part of the engine’s powertrain configuration, to fail. As a result, it is both beneficial and important to maintain DEF quality standards and testing.

For more information, contact us.

Why Should Your Laboratory Participate?

You receive test results available only to participating laboratories that will help you:

  • Monitor strengths and weaknesses of your laboratory's performance
  • Periodically compare your test results and calculated statistical parameters with other laboratories

Should you have an issue with your published results, please write to with your lab number and account number.

Test Materials

Two liters of diesel exhaust fluid will be used in the program for each test cycle.

Test Parameters

Test Parameters (subject to change):

ISO 22241-5 — 2012 Diesel engines

Nox reduction agent AUS32

ISO 3675


ISO 12185

Density at 20C

ISO 22241-2

Annex B/C Urea Content Refractive Index

ISO 22241-2

Urea Content (Total Nitrogen)

ISO 22241-2

Annex C Refractive Index at 20C

ISO 22241-2

Annex D Alkalinity as NH3

ISO 22241-2

Annex E Biuret content

ISO 22241-2

Annex F Aldehydes content

ISO 22241-2

Annex G Insoluble Matter content

ISO 22241-2

Annex H Phosphate (PO4)

ISO 22241-2

Annex I Ca, Fe, Cu, Zn, Cr, Ni, Al, Mg, Na, K

ISO 22241-2

Annex J Identity (FTIR)


Urea Concentration

NOTE: List of Methods Subject to Change. Participation is not contingent upon performing all program tests.

Distribution Of Samples

Test samples are prepared and distributed for ASTM International by SGS North America Deer Park, TX. Program registration fees include the cost of shipping test samples to U.S. participants or, for international participants, to a third party shipping agent located in the U.S.

IMPORTANT for Intercontinental participants: You have the following options for receipt of samples:

  • Ship through a third party shipping agent - Provide ASTM International with the complete contact information of a designated Shipping Agent located in the U.S. who will be responsible for shipping samples from the U.S. to your facility. Participants are responsible for making financial and shipping arrangements directly with the shipping agent.
    • Please be advised that when samples are shipped, an e-mail is sent only to the contact of record on your ASTM PTP account. It is the customer’s responsibility to advise their designated shipper that the sample has been shipped.
    • We cannot permit shipping agents to pick up samples at our distributors’ warehouses.
  • Samples ship directly from the sample distributor via UPS, DHL, or FEDEX - Provide ASTM International with your shipping account number to cover shipping charges. Check that your carrier will deliver the test materials to your location. Materials classified as Hazardous may have restrictions.
    • You are responsible for additional fees charged-back to our distributor for any reason relative to your sample shipment including, but not limited to, fees for fuel surcharges, missing/invalid account numbers, dangerous goods, remote area delivery, and multiple delivery attempts.
  • Product Shipping Specs
    • Quantity: 2 x 1L bottles
    • Shipping Weight: 6 lbs
    • Dimensions: 4x9x10"
    • ECCN: EAR99
    • Harm Code: 3102.10.0030

Program Requirements

Upon completion of tests, each laboratory electronically submits their test data to ASTM for use in generating statistical summary reports. Reports contain:

  • Coded laboratory test results
  • Statistical analyses of test data
  • Charts plotting test results versus laboratory code
  • Histograms plus Box & Whisker Plots

About Astm International Committee D15

Committee D15 on Engine Coolants, consists of over 220 members and developers of over 55 ASTM standards, provides the technical direction for the program. Test information generated through the program is utilized by Committee D15 to determine if modifications to ASTM documents or new methods are warranted. Data submitted to Committee D15 is coded to maintain lab confidentiality.