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By Jeremy Bond and Polona Carson
Feb 27, 2026
ASTM International launched the reference material product line in 2022, focusing on producing reference materials (RMs) for the petroleum industry.
The increase in petroleum testing laboratories pursuing ISO/IEC 17025 accreditation increased the need for RM and certified reference materials (CRMs), thus increasing the need for reference material producers (RMPs) to be ISO 17034 accredited to supply the demand.
Table 1: Key Differences Between Accredited and Non-Accredited RMs
| Characteristic | Accredited Reference Material (CRM/RM) | Non-Accredited Reference Material |
| Producer Status | Verified by an accreditation body (e.g., A2LA, ANAB) to meet ISO 17034. | Not independently audited; quality relies solely on the manufacturer's internal claims. |
| Traceability | Fully traceable to international standards (SI units). | May or may not be traceable; lacks third-party verification of that link. |
| Uncertainty | Includes uncertainty of mean value in a unit over product lifetime. | Usually provides only a single value with no stated margin of error. |
| Stability/Homogeneity | Backed by rigorous, documented testing over time and across batches. | May vary between bottles or degrade without a defined shelf-life study. |
| Documentation | Accompanied by a certificate of analysis (CoA) with an accreditation seal. | Often only a "Product Info Sheet" or "Specification Sheet." |
For ASTM, the decision to become an ISO 17034 accredited RMP aligned with the organization’s strategic objective to be an innovative services provider. It additionally built upon ASTM’s position as an ISO 17043-accredited proficiency testing (PT) provider, trusted by laboratories globally.
In 2024, ASTM underwent assessment by A2LA, an accreditation body that independently verified that ASTM meets the rigorous requirements of the general requirements for the competence of reference material producers (ISO 17034:2016).
As an accredited RMP, ASTM can offer a wide selection of accredited RM and CRM to support the growing needs of quality-focused laboratories around the world.
ASTM RMs are characterized through a consensus testing approach, leveraging the size and breadth of ASTM’s interlaboratory PT programs and utilizing published ASTM consensus standards. Homogeneous and stable materials are distributed to multiple laboratories, and the laboratories analyze the materials by a number of standard test methods. The analytical results are collected, the data sets are statistically processed, and the material is characterized as RM or CRM. The characterization yields operationally defined, method-specific values with traceability to the respective standard test method. Additional statistical evaluations further assure the homogeneity and stability of RM/CRM production batches and confirm the RM/CRM is fit for the intended use.
What really sets accredited RMs apart is a rigorous and statistically based approach to the assignment of property values and their uncertainty.
Property value is an assigned quantitative or qualitative value for a specific characteristic of the material. According to ISO 17034, for a value to be considered a certified property value and reported on CRM certificate, it needs to consist of the value, the uncertainty, and the traceability to international standards. For accredited RMs, reporting uncertainty and traceability is optional.
The certified value, presented as a number (e.g., concentration) is the best estimate of the true value and is most commonly determined from the mean of multiple measurements. For ASTM CRMs and RMs, all measurements are made by specific ASTM method. Because no measurement procedure is perfect, the property value must include the estimation of error expressed as uncertainty. The last component, metrological traceability, links property value to primary reference, usually the International System of Units (SI), through an unbroken chain of comparisons.
ISO 17034 requires that appropriate statistical methods be used for property value and uncertainty assignments. Recommended statistical concepts and approaches for RM production are provided in RMs — approaches for characterization and assessment of homogeneity and stability (ISO 33405:2024), formerly known as ISO Guide 35. Evaluation of ASTM CRMs and RMs follows these concepts applied to petroleum products, as described in applicable ASTM standards.
Samples from a production batch with previously confirmed homogeneity are distributed in the ASTM PT program. Results are first screened for potential outliers following procedures described in the standard practice for application of generalized extreme studentized deviate (GESD) technique to simultaneously identify multiple outliers in a data set (D7915). Data are then analyzed per the standard guide for analysis and interpretation of proficiency test program results (D7372). The final result is the property value of the RM (e.g., certified concentration of measurand) with an estimate of its uncertainty. Only results for laboratories that can demonstrate competency — either through accreditation that confirms their compliance with ISO/IEC 17025 or a history of their performance in this program — are considered for assignment of a CRM property value, a premium product in comparison to accredited RM.
Assessment of RM/CRM batch homogeneity proves that property value is the same in every packaged unit produced in a batch and sold to the customer. Following ISO 33405:2024, ASTM evaluates homogeneity using a one-way ANOVA approach. Between-unit and within-unit variability are evaluated and constitute a component in total uncertainty of the property value.
The last piece in CRM and RM evaluation is property value stability, which needs to be demonstrated over the lifetime of RM and is reported as “expiration date” on the RM product information sheet or CRM certificate. Collecting data over the lifetime of a product takes time; therefore, newly accredited RMPs such as ASTM are allowed to assign initial expiration dates based on historical records and knowledge of RM performance. However, they must also set aside a sufficient number of units in their original packaging and collect data over the lifetime of product to confirm its stability. Collected data are most commonly analyzed using regression analysis. A product’s expiration date is determined based on the comparison of regression slope and its prediction interval to allowance for property value change due to degradation. Commonly, degradation acceptance criteria are set to site precision of measurement error. If the RMP can demonstrate that change in the property value is not greater than the expected variation due to site precision, the property value is deemed stable. Stability of ASTM RMs is currently estimated from historical results obtained on the same material over multiple PT cycles.
Finally, total standard uncertainty assigned to the CRM property value is estimated as the square root of the sum of contributing squared standard uncertainties.
Currently, ASTM uses this rigorous approach for production of a wide range of certified reference materials for instrument and laboratory analyst competence verification to support petroleum industry requirements. ●
Jeremy Bond is a director of program management within Laboratory Services at ASTM International. Prior to joining ASTM, he spent 15 years in the commodities testing, inspection, and certification (TIC) industry.
Polona Carson, Ph.D., MBA, is senior scientist and project manager at Neptune and Co. Carson is also a vice chair of the committee on quality and statistics (E11). John Carson, Ph.D., is senior statistician for Neptune and Co. and the Data Points column coordinator. Carson is the current chair of E11.30 and a member of the committees on quality and statistics (E11); petroleum products, liquid fuels, and lubricants (D02); air quality (D22); environmental assessment, risk management, and corrective action (E50);
John Carson, Ph.D., is senior statistician for Neptune and Co. and the Data Points column coordinator. Carson is the current chair of E11.30 and a member of the committees on quality and statistics (E11); petroleum products, liquid fuels, and lubricants (D02); air quality (D22); environmental assessment, risk management, and corrective action (E50); and personal protective clothing and equipment (F23).
March / April 2026
