Maintaining QC Types and Assessments

• Maintaining QC Types and Assessments
  • QC Type Scope
  • Properties of a QC Type
  • Use of QC Types
  • Configuring QC Types
  • Configuring a QC Type to Assess Duplicate or Replicate Pairs of Standard or blank QC Samples
  • Configuring QC Type Assessment by Script
  • QC Types Creation and Maintenance
  • QC Type Dependencies and Restrictions

A QC type denotes an auxiliary type of QC assessment that is applied, using custom script, when a sample that has a primary or secondary analytical type of Duplicate, Replicate, Blank, Standard or Spike receives a result. Effectively, a sample's Primary QC Type and Secondary QC Type allows the sample to undergo a two types of auxiliary QC assessments after their fundamental QC assessments.

QC Type Scope

QC types are created either with org-scope or lab-scope. An organisation or laboratory can contain multiple QC types.

QC types are scoped by analytical type: Duplicate, Replicate, Blank, Standard or Spike.

Properties of a QC Type

A QC type can have:

• A QC script—Custom rules to be applied for an auxiliary type of QC assessment.
• A secondary analytical type—An allowable secondary QC assessment for a sample of the given analytical type.

Use of QC Types

When CCLAS is first installed, it comes with basic QC types for each analytical type: Duplicate, Replicate, Blank, Standard and Spike.

An analytical type denotes the fundamental type of QC assessment that is applied when a sample that has a primary or secondary analytical type of Duplicate, Replicate, Blank, Standard or Spike receives a result. Effectively, a sample's Primary Analytical Type and Secondary Analytical Type allows the sample to undergo a two types of fundamental QC assessments.

The combination of primary and secondary analytical type defines the type of QC sample which drives its subsequent assessment.

A sample's Primary Analytical Type and Secondary Analytical Type are used to apply fundamental QC assessment to the sample's results. Results held in QC history can be accessed using the primary and secondary analytical type.

A sample's Primary QC Type and Secondary QC Type are used to apply auxiliary QC assessment to the sample's results, by applying rules in a custom script. Results held in QC history can be accessed using the primary and secondary QC type.

A sample's primary analytical type and QC type, and secondary analytical type and QC type, can be set by:

• The user when a QC sample is registered.
• By the QC mask member that caused the QC sample to be created when an append or overwrite QC process was run on a job.
• By the QC mask member that caused the QC sample to be created when a laboratory batch job was created.

These settings can be updated by editing the sample or during QC sample maintenance launched during a workbook session.

Configuring QC Types

To configure a typical analytical sub-type, a QC type is created with the Primary QC Type selected to match the base analytical type. For example, if you select the Primary Analytical Type as Standard, then you would typically select STD, or something similar, for the Primary QC Type.

Examples: QC types that could be applied to client samples

• Hidden standard—A client-supplied sample, but the client is treating it as a standard, and they already know the expected value ranges, but the laboratory might not (or is not supposed to) know the expected values, however, it is clearly identifiable as being different to the true client samples.
• Hidden blank—A client-supplied sample, but the client is treating it as a blank, and they already know the expected value ranges, but the laboratory might not (or is not supposed to) know the expected values, however, it is clearly identifiable as being different to the true client samples.
• Field duplicate—A client-supplied sample, but the client is treating it as a duplicate that was taken out in the field, and they already know which samples make up the pair. The laboratory does not really know which is the duplicate pair (unless there is some clue from the sample details from the client). At best, it is only once the sample is identified as a field duplicate and the rest of the results are available, that the laboratory could possibly identify which samples make up the pair. The field duplicates can (because of the errors in sampling) have quite different result ranges, and the client uses this to measure the efficiency of the field sampling techniques to get a representative sample.
• Hidden duplicate—A client-supplied sample, but the client is treating it as a duplicate, and they already know which samples make up the pair. The laboratory does not really know which is the duplicate pair (unless there is some clue from the sample details from the clients). At best, it is only once the sample is identified as a hidden duplicate and the rest of the results are available, that the laboratory could possibly identify which samples make up the pair.
• Hidden check—A client-supplied sample, but the client is treating it as a check (maybe from some previously supplied sample), and they already know what the original results were. The laboratory may be aware of this type of check sample, as it probably already in a 'prepared state' and is typically not the same size nor weight as the other samples. The laboratory does not really know which is the original sample (unless there is some clue from the sample details from the client).

Examples: QC types that could be applied to QC sample, that is, to a standard, blanks or spike

• Matrix blank—Identifies that the blank represents a matrix similar to the other samples, and that it is processed entirely in the same way as the client samples are processed.
• Reagent blank—Identifies that the blank is just made up of the reagents used in the test, and no blank material was treated initially.
• Rinse blank—Identifies that the blank is inserted at the instrument and represents the measuring of rinse solution, between real samples on the instrument. This gives and indication how much the reading of one sample can effect the reading of the next sample.
• Calibration standard—Identifies that the standard is used by the calibration process of the test rather than to check the calibration/accuracy of the test (which is usually the reason for using standards).
• Calibration blank—Identifies that the blank is used by the calibration process of the test rather than to check the calibration/accuracy of the test (which is usually the reason for using blanks).
• Standard duplicate—Identifies that the standard is treated as a duplicate, that is, a pair of standards are measured, and whilst each needs to pass standard assessment, together they need to pass duplicate assessment.
• Standard spike duplicate—Identifies that the spike is treated as a duplicate, that is, a pair of spike standards are measured, and whilst each needs to pass spike assessment, together they need to pass duplicate assessment.

When defining a QC mask, multiple QC samples can have the same primary analytical type but a different primary QC type. For example, to add 2 blanks to a rack where one blank is treated as a reagent blank and the other as an instrument rinse blank, then the QC mask could contain:

• Primary Analytical Type = Blank, QC Type = REAGENT_BLANK
• Primary Analytical Type = Blank, QC Type = RINSE_BLANK

Configuring a QC Type to Assess Duplicate or Replicate Pairs of Standard or blank QC Samples

In the case where a reference standard or blank requires duplicate or replicate assessment between pairs of these samples, then two QC types are created, and the second linked to with the first.

Example: CRM and CRMDUP duplicate pair.

The CRM QC type is created with a Primary Analytical Type of Standard. The CRMDUP QC type is created with a Primary Analytical Type of Standard AND a Secondary Analytical Type of Duplicate, and is associated with the CRM QC type for the duplicate assessment. When the CRM QC type is selected in a QC mask, or when a QC sample is added to an existing rack of samples, if more than one standard is created for that QC type, then you have the option to create the second and subsequent standards as a standard duplicate QC sample.

Configuring QC Type Assessment by Script

Although CCLAS provides core precision and standard assessment, custom assessment rules may be configured.

Where a sample has a Primary Analytical Type or Secondary Analytical Type of Blank, Standard or Spike and a sample scheme analyte is active for QC assessment, when the sample scheme analyte obtains a result:

• The result undergoes core standard assessment to set the sample scheme analyte's Standard Status.
• After core standard assessment, if the sample's Primary QC Type or Secondary QC Type for that standard assessment is linked to a Script, then the script is run to perform custom standard assessment based upon the QC type.

Where a sample has a Primary Analytical Type or Secondary Analytical Type of Duplicate, Replicate or Spike and a sample scheme analyte is active for QC assessment, after standard assessment:

• The result undergoes core precision assessment to set the sample scheme analyte's Precision Status.
• After core precision assessment, if the laboratory is linked to a Precision Assessment Script, then the script is run to perform custom precision assessment for the laboratory.
• After laboratory-wide precision assessment, if the sample's Primary QC Type or Secondary QC Type for that precision assessment is linked to a Script, then the script is run to perform custom precision assessment based upon the QC type.

QC Types Creation and Maintenance

QC types are created and maintained using the CCQCTP—QC Type application, which is also accessed using the Analysis Setup » QC Types menu option.

QC Type Dependencies and Restrictions

QC types created at organisation level can be used at laboratory level, but cannot be altered.