Post Analytical Correction Factors
Background and Innovation
Post-analytical correction factors (PACFs) are vital tools used in clinical laboratories to standardise patient results across differing instruments, methods, or reagent lots. By accounting for systematic biases, PACFs ensure the accuracy, consistency, and clinical comparability of patient data across a laboratory network. However, while PACFs are essential for patient testing, they must never be applied to EQA or QC results due to the non-commutable nature of EQA materials.
Recognising this critical distinction, the Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP) has delivered a world-leading innovation: the first automated de-factoring feature for EQA result submissions, integrated into our myQAP portal.
Should you be de-factoring quantitative survey results before submission?
Common scenarios where PACFs may be appropriate include:
- Aligning patient results across different methods or instruments that quantify the same measurand within a laboratory network
- Correcting for biases introduced by a new reagent lot or calibrator, which would otherwise necessitate adjustments to reference intervals or clinical decision points.
If your laboratory adjusts patient results for any of the reasons above, de-factoring of survey results must be completed before submitting them to the RCPAQAP surveys.
The Solution
RCPAQAP has developed and implemented a first-of-its-kind, automated de-factoring engine within the myQAP portal. This tool:
- Automatically de-factors PACFs that have been applied to survey results
- Allows laboratories to flag and reverse PACFs during data submission
- Ensures survey results reflect the laboratory’s true performance without artificial correction
A short instructional video is available to demonstrate the set up of the de-factoring of survey results.
If you wish to use this feature, please submit a request through our customer portal to have this functionality activated for your participant ID/s. When factoring is activated, it will be applied to all programs where factoring is available.
Impact and Benefits
This advancement:
- Elevates the integrity of EQA results at scale.
- Ensures accuracy in EQA result comparisons by eliminating biases from non-commutable survey materials.
- Reduces manual intervention, decreasing the risk of transcription errors.
- Supports regulatory compliance and best practices in laboratory result reporting.
- Reduces burden and risk for laboratories using automated PACF workflows.
1. Roger Barton, Mark Mackay, Graham Jones, Tony Badrick. The Management of Post-Analytical Correction Factors. Clin Biochem Rev. 2017 Apr;38(2):101-103
Schematic Representation of de-factoring survey results in the RCPAQAP Customer Portal
Figure 1: Result entry page displaying the icon that appears when requesting the feature to de-factor survey results.
a. The icon will appear against all measurands. The colour of the icon will determine if factors have been applied to a measurand. A grey icon will suggest no de-factoring has been applied to a measurand.
b. The reported value that has been entered by the participant.
c. The submitted value is the reported value that has been de-factored. This value is the result that has been submitted for analysis in the RCPAQAP surveys.
Figure 2: Clicking on the ‘factor’ icon will open a window allowing you to enter the required factors applied to a measurand.
a. Clicking the drop-down arrow will display information on when to apply a factor to a survey result.
b. Represents the applied factors that were used to calculate the ‘reported’ result issued to the clinician. The ‘relative factor’ represents when the patient results are multiplied or divided by a value and the ‘absolute factor’ represents when the value is added to or subtracted from the patient result.
c. Participants can include the reason why the factoring is applied to the reported result.
d. Displays the calculation to de-factor the reported result (the reverse calculation).
Figure 3: The submitted results tab will provide participants with the ‘Reported’ result entered by the participant and the ‘Submitted’ result (calculated by the ‘factor applied’ to the measurand, displayed in a separate column).