Algorithmic Ascorbic Acid Detection on Urine Reagent Pads

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Solution Overview

Problem

Ascorbic acid in urine samples can cause false negatives in urinalysis assays by interfering with reagent pads, particularly those designed for glucose and blood, leading to inaccurate readings due to 'bleaching' effects, which existing methods struggle to address without additional space for ascorbic acid-specific pads.

Innovation Solution

The implementation of algorithms and methods that utilize Dispense Detection and Ascorbate Algorithms on non-ascorbic acid reagent pads, such as glucose and blood pads, to detect ascorbic acid by measuring changes in RGB reflectance values, allowing for detection without additional pads and accounting for interference effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If ascorbic acid reagent pads are added to the test strip to detect ascorbic acid, then ascorbic acid detection capability is improved, but test strip space is insufficient and device complexity increases

Engineering Contradiction:
Improveascorbic acid detection capabilityVSAvoidtest strip space
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent applies multi-functionality by enabling existing reagent pads (designed for detecting substances like glucose, blood, bilirubin, ketone, urobilinogen, nitrite, leukocyte esterase, or albumin) to also detect ascorbic acid interference. The system measures color intensity changes on these pads and uses algorithms to determine if ascorbic acid is present based on abnormal color changes that differ from normal analyte detection patterns.

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

Solution Approach 2:

The system uses the existing reagent pads' color change responses to serve dual purposes: detecting their intended analytes and simultaneously detecting ascorbic acid interference. The algorithms analyze the color intensity measurements to self-identify when ascorbic acid is present, eliminating the need for separate dedicated ascorbic acid detection pads.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If additional test strips are used to detect ascorbic acid, then ascorbic acid detection is improved, but limited space in the analysis machine is required

Engineering Contradiction:
Improveascorbic acid detection capabilityVSAvoidanalysis machine space
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent enables a single test strip and analysis machine configuration to perform multiple functions: detecting the primary analyte (such as glucose or blood) and simultaneously detecting ascorbic acid interference. This is achieved through algorithms that analyze color intensity measurements from existing reagent pads to determine the presence of ascorbic acid, eliminating the need for separate test strips or additional machine space.

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

Solution Approach 2:

The system merges the detection functions for primary analytes and ascorbic acid into a single integrated process. The analysis machine processes one test strip to provide both the primary analyte result and the ascorbic acid interference status, combining multiple detection capabilities into one unified system that saves space and simplifies operation.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If reagent chemistry on reagent pads is altered to add resistance to ascorbic acid effects, then false negatives are reduced, but manufacturing complexity increases

Engineering Contradiction:
Improveresistance to ascorbic acid interferenceVSAvoidreagent chemistry complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The system uses feedback by measuring the actual color intensity changes on reagent pads and comparing them against expected patterns. The algorithms analyze whether color changes are consistent with the presence of the intended analyte or indicate ascorbic acid interference, allowing the system to compensate for interference effects without requiring complex chemical modifications to the reagent pads themselves.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies parameter changes by using algorithms to interpret color intensity measurements in the context of potential ascorbic acid interference. The system changes the analytical approach from simple colorimetric detection to algorithm-based interpretation that accounts for interference patterns, maintaining simple reagent chemistry while improving reliability through sophisticated data analysis.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accurate detection of ascorbic acid in urine samples using existing reagent pads, preventing false negatives and maintaining test strip compactness, thereby improving diagnostic accuracy without the need for additional test strips.

Implementation Method 1

The test strip usually has one or more test areas ('reagent pads') that are capable of undergoing a color change in response to contact with the patient sample

Methodology Applied
Scientific EffectColor change:

Implementation Method 2

the presence of ascorbic acid in the sample reduces the reagent signal on the glucose reagent pad resulting in a negative glucose reading (i.e false negative) or a reduced glucose reading

Methodology Applied
Scientific EffectBleaching effect:

Data Source

PatentEP3532828B1Detection of ascorbic acid in a urine sample
Publication Date: 2024.05.08 SIEMENS HEALTHCARE DIAGNOSTICS INC
  • EP3532828B1 patent drawingFigure 1
  • EP3532828B1 patent drawingFigure 2A~2B
  • EP3532828B1 patent drawingFigure 3A~3B

AI summary

Disclosed herein are methods of detecting ascorbic acid in a urine sample from a subject. The methods comprise contacting at least a portion of the urine sample with a test strip comprising a reagent pad and detecting whether ascorbic acid is present in the urine sample. The detecting comprises measuring an intensity of color on the reagent pad, wherein a reduction in the intensity of color on the reagent pad indicates the presence of ascorbic acid.