CUSUM Rule for Selective Specimen Retesting in Clinical Diagnostics

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current clinical diagnostic processes face inefficiencies in detecting and addressing large out-of-control conditions, leading to unnecessary retesting of specimens, as existing quality control methods often fail to accurately identify the onset and scope of errors, resulting in duplicative testing and resource burdens.

Innovation Solution

A system and method that automatically identifies large out-of-control conditions, estimates the number of incorrect results, and applies a CUSUM rule to re-evaluate specimens, thereby pinpointing the origin of the error and retesting only affected specimens, reducing unnecessary retesting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all patient specimens are retested after an out-of-control condition is detected, then reliability of results is improved, but productivity deteriorates due to unnecessary duplicative testing

Engineering Contradiction:
Improvereliability of diagnostic resultsVSAvoidtesting efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the retesting process by dividing specimens into two groups: those tested during an out-of-control condition (which require retesting) and those tested during in-control conditions (which do not require retesting). This segmentation allows the system to selectively retest only the necessary specimens rather than all specimens, thereby maintaining reliability while improving productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by retesting only the portion of specimens that were actually affected by the out-of-control condition, rather than performing excessive retesting on all specimens. The system uses quality control data to determine the exact timeframe of the out-of-control condition and retests only specimens processed during that specific period, eliminating unnecessary duplicative testing.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If the testing process is halted to identify unreliable results, then measurement precision is improved, but loss of time increases

Engineering Contradiction:
Improveaccuracy of diagnostic resultsVSAvoidtime to resume testing
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary identification of unreliable results by using quality control data to automatically determine the timeframe of out-of-control conditions before reporting results. The system pre-identifies which specimens are affected by tracking the timing of quality control failures relative to specimen processing times, allowing rapid identification without halting the entire testing process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where quality control results are continuously monitored and used to automatically adjust the status of patient specimens. When quality control failures occur, the system provides feedback to identify affected specimens and triggers automatic retesting only for those specific specimens, enabling continuous operation while maintaining precision.

Inventive Principle:
Principle #23Feedback

3Reliability

If quality control rules are made more stringent to detect out-of-control conditions, then reliability improves, but device complexity increases

Engineering Contradiction:
Improvedetection of out-of-control conditionsVSAvoidquality control system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by using a single quality control system that performs multiple functions: it monitors quality control materials, automatically determines out-of-control timeframes, identifies affected patient specimens, and triggers selective retesting. This multi-functional approach consolidates what would otherwise require separate complex systems into one unified solution, maintaining high reliability while managing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2980716B1System and method for recovering from a large out-of-control condition in a clinical diagnostic process
Publication Date: 2020.09.02 BIO RAD LABORATORIES INC
  • EP2980716B1 patent drawingFigure 1
  • EP2980716B1 patent drawingFigure 2
  • EP2980716B1 patent drawingFigure 3A

AI summary

Disclosed are a system and method to recover from a large out-of-control condition in a clinical diagnostic process. Upon detection of a large out-of-control condition, a CUSUM rule is designed to predict if specimen test data was produced during the occurrence of that condition. Specimen test data is re-evaluated and the CUSUM rule is applied to determine whether to accept or reject the test results. Upon completion of the re-evaluation, old test results identified as being invalid are replaced with the the new, re-evaluated results and the new results are published if publication did not occur previously.