Assessing Results against Product and Specification Limits

Overview

Product and specification assessment is a component of quality assessment applied to unknown samples.

Some samples submitted for testing are specific in nature and purpose, and are of known materials. Specifications contain the typical range of results that are expected for a material. When a sample is associated with one or more specifications, the results of the sample is assessed against those typical ranges. These specification limits could come from:

  • Industry norms
  • Client supplied or requested limits
  • Reportable limits
  • Specifications associated with the specific tests
  • Alerts that the laboratory adds to the sample to assist in its internal verification and validation steps (refer to primary product assessment)

Some samples are so specific in nature and purpose that they are of a known product. Products are usually associated with one or more specifications. When a sample is associated with a product, it is associated automatically with the specifications of that product.

It may be helpful to review a product and any applicable certification limits to understand the specification requirements for the analytes in the schemes to be tested. This also provided an at-a-glance check of whether the product specifications are current according to the certification prerequisites.

The specification limits are specific to the analysis conducted (as indicated in the scheme, version, analyte and unit of analysis, or multiples of these as applicable to the sample). Specification limits might include a warning range as well as a failure range.

Ultimately, the outcomes of the testing demonstrates whether the sample (or samples) adheres to the standards required for the material, or for certification.

In CCLAS, the assessment of unknown sample results against the specifications either related to the product, or not related with any product, is known as specification assessment, and sets the specification status for the analysis against the individual specifications. The resulting specification status indicates whether the results of assessment for the sample meet the quality requirements (that is, falls within the specification limits).

Specification limits for analytes with a Data Type of Numeric and Numeric Only might include a warning range as well as a failure range.

Specification lists for analytes with a Data Type of Text can be case-sensitive or insensitive.

If a sample of a known product achieves results outside of these typical ranges, then the laboratory has a few options available to them:

  • The test results might be wrong (through a failure of the test to report the correct result). In this case, if the tests are repeated (maybe via an alternative method, operator or instrument), then this gives confidence to the laboratory that the results were accurate.
  • The sample might be mis-labelled within the laboratory's control or contaminated by the laboratory’s processes. Steps might be required to see if a primary sample portion is available as a potential re-test portion.
  • The material might be different to the expected material (through a failure to obtain a correct sample, contamination, mis-labelling by the client or sampling process, failing in the production environment etc). In this case, as long as the laboratory has excluded the first potential problem, the laboratory cannot do much, except report the results to the client along with any suitable warnings. This might trigger the client to provide another sample (as a cross-check) or to react as if the results are correct for the sample presented to the laboratory.

Some laboratories have an early warning requirement to the client. That is, if a preliminary result is not within the typical ranges, the client then has as much notice as possible for the potential reporting of unacceptable results.

As indicated earlier, if the sample presented to the laboratory does not represent the original bulk material, then the failure of the tests to confirm the specifications of the product may be because of that reason.

Assessing the product quality of samples is a component of quality assessment applied to unknown samples when the sample is linked to specifications, particularly for when the sample is associated with a product. That is, product assessment is specification assessment, where the addition of the product to the sample adds the product's specifications to the sample.

Primary Specification Assessment

Some samples submitted for testing are so specific in nature and purpose that various analytes contained within the material must be within a typical range of results, and it is so critical that the analysis must be held up and considered to be incomplete if the amount of analyte falls outside of expected limits. The primary specification assessment is used for QC purposes such that if a result fails the primary specification, then the workflow status is impacted. This is typical of production plants where immediate indications must be made if an analyte falls outside of the expected specification.

Process

Creating the Scheme, Version and Analytes

Schemes are configured using the CCSCHM—Scheme application.

For a sample scheme analyte's result to be assessed for scheme or surrogate limits, the following conditions must hold:

  • The scheme version analyte must have a Data Type of Numeric, Numeric Only or Text.

  • The scheme version analyte must have a Unit Code.

    Important: This also applies to text analytes, in which case, if there is no unit, create a unit called NO_UNIT and use that, for example.

  • The scheme version analyte's QC Active must be selected.

Configuring Products

Products are maintained using the CCPRDT—Product application.

A product can link to one or more active specifications that have a Specification Type of Product, to create product specifications.

Products must be activated for use.

Adding Limits for the Product Specification

Update the product specification to add the specification limits for the scheme version analyte units. Specifications are configured using the CCSPFN—Specification application.

A specification can contain multiple entries for scheme, version, analyte and unit.

For a sample scheme analyte's result to be assessed for product specification limits, the specification must contain an entry for the related Scheme Code, Scheme Version, Analyte Code and analysis Unit Code.

Important: This also applies to text analytes, in which case, if there is no unit, create a unit called NO_UNIT and use that, for example.

Product specifications, for the primary product specification, are treated as critical for validation only where the specification scheme version analyte is Critical For Validation is selected.

Numeric and Numeric Only Analytes

Where the scheme version analyte has an Analyte Data Type of Numeric or Numeric Only, scheme limit assessment uses the specification scheme version analyte's internal absolute limits, where the warning and failure ranges are absolute.

There is the option to enter these limits as relative values, where a percentage around the target value for warning and failure limits is designated, however, the system determines the equivalent absolute values and uses them for the accuracy assessment.

A specification scheme version analyte unit's numeric limits are bound by any or all of the following:

  • < or = Internal Minimum Value—The lowest acceptable amount of substance for the specification to be satisfied, below which the material would fail the standard lot's specification.
  • < or = Internal Minimum Warning Value—The lowest acceptable amount of substance for the specification to be satisfied without warnings, below which the material would satisfy the standard lot's specification but with warnings.
  • Internal Target Value—The target value for the acceptable amount of substance in the material.
  • > or = Internal Maximum Warning Value—The highest acceptable amount of substance for the standard lot's specification to be satisfied without warnings, above which the material would satisfy the specification but with warnings.
  • > or = Internal Maximum Value—The highest acceptable amount of substance for the standard lot's specification to be satisfied, above which the material would fail the specification.

Text Analytes

Where the scheme version analyte has an Analyte Data Type of Text, the specification can be configured to assess strings with or without case-sensitivity.

Note: Leading and trailing spaces are not removed upon cell exit but are removed upon submit. Therefore, if a list of expected results in an applied specification contains "DEF" and not "DEF " for a text analyte, and "DEF " is entered into the cell, then upon cell exit, the cell is flagged red to show a failed specification assessment. However, upon submit, leading and trailing spaces are removed, so "DEF" is persisted, such that, upon workbook reload, if the cell undergoes Force Reassessment, then the cell shows a passed specification assessment.

Linking Samples to Products and Specifications

A sample can link to an active product to set the sample's Product Code. When this occurs, then the sample then inherits the product's specifications, and the primary specification on the product becomes the sample's Primary Specification Code.

A sample can link to one or more active specifications that have a Specification Type of Product but not necessarily associated with a product, to create additional sample specifications, however, the Primary Specification Code does not default to any particular sample specification from specifications added this way.

Where a template job is used to register a job, the Product Code and Primary Specification Code are inherited from the template and applied to the job sample (or samples). This is also the case where a sample template is used to register a sample. The sample specifications created for the sample inherit the values set in the sample template.

Where a sample scheme analyte specification is created or the sample scheme analyte's result is cleared, then the sample scheme analyte specification's Standard Status is set to Not Tested.

After sample creation, a sample's Product Code can be updated and sample scheme analyte specification records can be previewed, with the ability to set other user-defined specification limits for use during reporting phases, on the Specification tab of the CCCSAMP—Sample Update screen. In addition to the user-defined specification limits, all of the specification scheme version analyte record's properties can be displayed as read-only on this form, and the sample scheme analyte specification's Reportable flag, which was inherited from the specification scheme version analyte, can be set for use during reporting phases.

Where the specification was added via a product or loose specification (that is, by not using a template sample), when a change is made to the sample scheme analyte specification in the way of user-defined specification limits or reportability, then the virtual sample scheme analyte specification records are persisted to hold the altered information. If no change is made and these records are still virtual, then the sample scheme analyte records are not actually persisted until specification assessment.

Refer to Maintaining Sample Product and Specifications.

Note: This is important to note for report designers. It cannot be relied on that the sample scheme analyte specification records are persisted, and therefore physically present for during report generation. In this case, these records must be constructed in a report script, from the original specification scheme version analyte.

Therefore, a sample can link to multiple product specifications, one of which can be flagged as the primary product specification. A sample's product specifications impact a sample scheme analyte's composite specification assessment, but a sample's primary product specification impacts a sample scheme analyte's composite QC assessment, as follows.

Assessing Results against Product Specifications

When specification is added to a sample, each sample scheme analyte specification's Specification Status defaults to Not Tested, and the sample scheme analyte's Composite Specification Status defaults to Not Tested.

When a result is received or cleared for a sample scheme analyte, specification assessment occurs using the absolute internal lower failure, lower warning, target, upper failure and upper warning limits from the product specifications attached to the sample:

  • Each sample scheme analyte specification's Specification Status is set based on the specification's limit assessment.

    • The sample scheme analyte specification's Specification Status is set to Not Required where either:

      • The sample's Primary Analytical Type is Duplicate, Replicate, Blank, Standard or Spike, or

      • The scheme version analyte's Is QC Active check box is cleared, or

      • The specification does not contain a record matching the related Scheme Code, Scheme Version, Analyte Code and analysis Unit Code.

    • Otherwise, the sample scheme analyte specification's Specification Status is set to Passed, Lower Warning, Upper Warning, Lower Failure or Upper Failure by assessment against the specification scheme version analyte's limits for the related Scheme Code, Scheme Version, Analyte Code and analysis Unit Code.

  • Each sample scheme analyte specification's Specification Status is rolled up to set the sample scheme analyte's Composite Specification Status.

    When the system is assessing a sample scheme analyte's Specification Status, it sets the sample scheme analyte's Specification Status by considering the sample scheme analyte specification's Specification Status for the sample's Primary Specification, such that, where the Specification scheme version analyte's Critical for Validation is selected, then sets it to the sample scheme analyte specification's Specification Status, otherwise sets it to Not Required.

  • A sample scheme analyte's Specification Status is then rolled up to set the sample scheme analyte's Composite QC Status. In fact, the sample scheme analyte's Composite QC Status is set by cascading the sample scheme analyte's Scheme Limit Status, Precision Status, Standard Status and Specification Status. If a sample scheme analyte's Composite QC Status is one of the failure statuses, then the result cannot be validated until the cause of the failure is addressed.

Where the primary specification is NOT critical for validation:

  Sample Scheme Analyte Specification1 Sample Scheme Analyte Specification2
Sample Scheme Analyte Specification's Specification Status Failure Failure

Primary Specification?

 Y N
Critical for Validation? N Y
Sample Scheme Analyte's Composite Specification Status Not Required  
Sample Scheme Analyte's Specification Status (rolled up from the primary specification) Not Required  

Where the primary specification IS critical for validation:

  Sample Scheme Analyte Specification1 Sample Scheme Analyte Specification2
Sample Scheme Analyte Specification's Specification Status Failure Failure

Primary Specification?

 Y N
Critical for Validation? Y Y
Sample Scheme Analyte's Composite Specification Status Failure  
Sample Scheme Analyte's Specification Status (rolled up from the primary specification) Failure  

Note: Where a sample scheme analyte has a Primary Analytical Type of Unknown and the sample links to a standard lot that has a Specification Code of a specification that contains the matching scheme version analyte unit, when a result is entered or cleared for the analyte in the CCWKOP—Open Workbook application, such that, the system performs Assessing Results against Accuracy Limits to determine the sample scheme analyte's Standard Status, then the assessment is carried out as expected. Previously text-based assessment was not done. However, this enhancement has not been applied when Assessing Results against Product and Specification Limits.

The outcome of the assessments can be viewed in the lower panel of the CCWKOP—Open Workbook application. The outcomes of QC assessments can also be viewed in the CCVALN—Job and Sample Validation application.

Using Product Specifications in Reports

When a sample is included in a report, the reporting limits within the related product specifications are available for inclusion in the report result set.