Tmax Metric for Gastric Emptying Breath Test Diagnosis
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Solution Overview
Problem
Current gastric emptying breath tests face challenges in accurately diagnosing delayed and rapid gastric emptying due to limitations in the kPCD metric, leading to false negative diagnoses, especially at later time points, and require additional methods to differentiate normal and abnormal gastric emptying rates.
Innovation Solution
The method involves using Tmax, the time at which maximum 13CO2 excretion occurs, in combination with other breath test metrics and scintigraphic values to diagnose gastric emptying disorders, with cut-off values determined statistically from normal and abnormal subject data to differentiate between normal, delayed, and rapid gastric emptying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the kPCD metric is used for diagnosing gastric emptying disorders, then breath testing can be performed, but false negative diagnoses occur especially at later time points
Solution Approach 1:
The patent introduces Tmax (time of maximum 13CO2 excretion) as a new parameter to complement the existing kPCD metric. This parameter change allows differentiation of gastric emptying patterns that kPCD alone cannot distinguish, particularly resolving false negatives at later time points by capturing the temporal pattern of excretion.
Solution Approach 2:
The patent adds a temporal dimension to the diagnosis by measuring not just the amount of 13CO2 excreted (kPCD) but also when the maximum excretion occurs (Tmax). This dimensional addition transforms the diagnostic approach from a single-value metric to a time-resolved measurement, enabling better differentiation of gastric emptying disorders.
2Measurement precision
If multiple time points are measured to improve diagnostic accuracy, then sensitivity and specificity improve, but test complexity increases
Solution Approach 1:
The patent extracts the most diagnostically valuable information from multiple time point measurements by focusing on Tmax (the time of maximum excretion). Rather than requiring analysis of all time points, the method identifies and utilizes this single critical parameter, simplifying the diagnostic process while maintaining high accuracy.
Solution Approach 2:
The patent performs preliminary analysis of the breath test data to identify Tmax before making the final diagnosis. This preliminary identification of the critical time point allows clinicians to focus on the most informative aspect of the test results, reducing the cognitive load and complexity of interpretation.
3Measurement precision
If Tmax is used to differentiate normal and abnormal gastric emptying, then false negative diagnoses are reduced, but additional metrics beyond kPCD are required
Solution Approach 1:
The patent merges Tmax with the existing kPCD metric to create a comprehensive diagnostic approach. By combining these two metrics, the method achieves high diagnostic accuracy without requiring an extensive panel of separate tests, as Tmax and kPCD together provide sufficient information to differentiate all gastric emptying patterns.
Solution Approach 2:
The patent makes the breath test system multi-functional by enabling it to diagnose both rapid and delayed gastric emptying using the same test protocol and metrics (kPCD and Tmax). This universal approach eliminates the need for different tests for different conditions, reducing overall system complexity despite adding a metric.
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
This approach enhances diagnostic accuracy for gastric emptying disorders by providing a more reliable differentiation between normal and abnormal gastric emptying rates, improving sensitivity and specificity, and reducing false negative diagnoses, as demonstrated by comparison with gold standard scintigraphy methods.
Implementation Method 1
As the subject's digestive tract processes the 13C labeled food, a labeled digestive metabolite, 13CO2, is produced which can be detected in the subject's breath. The 13C label passes through the stomach, is absorbed by the small intestine and is metabolized by the liver to give rise to 13CO2.
Implementation Method 2
The amount of 13CO2 in a breath sample may be measured
Data Source
AI summary
A breath test and a breath test method for diagnosing abnormal gastric emptying using a 13C labeled breath test meal by identifying the time of maximum excretion of 13CO2 in the breath samples. The test and test method include supplying a subject with the breath test meal, collecting a breath sample of the subject at a plurality of time points after the subject consumes the meal, generating measurements of 13CO2 excretion from the breath samples, identifying a time Tmax at which 13CO2 excretion is maximal, comparing Tmax to a cut-off value. The subject may be diagnosed as having delayed gastric emptying if Tmax is greater than the Tmax cut-off value.