Fibrinogen Determination With Factor XIII for Single-Run Range

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Solution Overview

Problem

Existing methods for determining fibrinogen concentration, such as the Clauss method, have a limited measuring range, requiring multiple measurements at different dilutions due to rapid coagulation in samples with slightly elevated fibrinogen levels and insufficient clot formation in samples with low fibrinogen content.

Innovation Solution

The addition of Factor XIII to the reaction mixture extends the measuring range by stabilizing clots, allowing for a single measurement to determine fibrinogen concentrations across a broader range, including low levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the Clauss method is used with high thrombin concentration to determine fibrinogen, then the measuring range is limited and multiple measurements are required, but the method provides sufficient clot formation for detection

Engineering Contradiction:
Improvefibrinogen concentration determinationVSAvoidtime for multiple measurements
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent changes the thrombin concentration parameter to a low level (opposite of the high concentration used in Clauss method), which fundamentally alters the reaction kinetics. This parameter change enables a single measurement to cover a broad fibrinogen concentration range by creating a reaction profile with a clearly detectable lag phase even at low thrombin levels, eliminating the need for multiple measurements at different dilutions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a low thrombin concentration that is intentionally suboptimal for rapid clot formation. This partial action (using less thrombin than the Clauss method) creates a slower reaction that extends the measurable time window, allowing detection of fibrin formation across a broader concentration range in a single measurement

Inventive Principle:
Principle #16Partial or excessive action

2Productivity

If the Clauss method is used with high thrombin concentration, then rapid coagulation occurs in samples with slightly elevated fibrinogen levels, but this limits the measuring range

Engineering Contradiction:
Improvespeed of fibrin formationVSAvoidmeasuring range
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent creates a dynamic measurement system where the lag phase duration varies with fibrinogen concentration. By using low thrombin concentration, the system adapts to different fibrinogen levels by adjusting the observable lag phase length, enabling the same reaction conditions to measure across a broad concentration range from low to elevated levels

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent measures the lag phase (time before fibrin formation begins) as the primary parameter. This preliminary time measurement before actual clot formation provides information about fibrinogen concentration without being constrained by the speed of subsequent clot development, allowing accurate measurement even when final clot formation would be too rapid to distinguish between different concentrations

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If diluted plasma samples are used in the Clauss method to achieve low fibrinogen concentration, then the measuring range is extended, but this limits the measuring range in the lower fibrinogen concentration range

Engineering Contradiction:
Improvemeasuring range in upper concentration rangeVSAvoidmeasurement precision in lower concentration range
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

Instead of diluting the sample to extend the measuring range (conventional approach), the patent inverts the approach by using undiluted or concentrated samples with low thrombin concentration. This inversion allows the reaction kinetics to naturally accommodate a broad concentration range without sample preparation dilution, maintaining measurement precision across all concentration levels

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent creates a universal measurement system using low thrombin concentration that can handle both low and high fibrinogen concentrations in the same reaction conditions. This multi-functional approach eliminates the need for different measurement protocols (undiluted vs. diluted) that are required in the Clauss method, allowing a single procedure to accurately measure across the entire clinically relevant range

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

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

The method enables reliable determination of fibrinogen concentration in samples with low fibrinogen levels without the need for multiple measurements, reducing time and cost by clearly differentiating between low and higher concentrations.

Implementation Method 1

The coagulation protease thrombin (factor IIa) cleaves fibrinogen, thereby activating fibrin formation, i.e., clot formation

Methodology Applied
Scientific EffectCoagulation: Coagulation

Implementation Method 2

Factor XIII is known as the enzyme that plays a key role in clot formation by cross-linking fibrin strands. This cross-linking stabilizes the clot

Methodology Applied
Scientific EffectCross-linking: Chemical Bonding

Implementation Method 3

Due to fibrin formation, the reaction mixture becomes increasingly cloudy, allowing fibrin formation to be measured quantitatively using an absorption measurement

Methodology Applied
Scientific EffectAbsorption spectroscopy: Absorption Spectroscopy

Data Source

PatentEP4394045B1Method for determining fibrinogen
Publication Date: 2025.07.09 SIEMENS HEALTHCARE DIAGNOSTICS PRODS
  • EP4394045B1 patent drawingFigure 1A~1B
  • EP4394045B1 patent drawingFigure 2A~2B

AI summary

The present invention lies in the field of blood coagulation diagnostics and relates to an improved method for the quantitative determination of fibrinogen in a sample. The method comprises the addition of factor XIII to the reaction mixture.