Clinical Chemistry Instrument Calibration via LED Wavelength Correction
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Solution Overview
Problem
Clinical chemistry instruments face variability in sensitivity due to differences in wavelength band shape and centroid of light sources, leading to inconsistent measurements, especially for assays like calcium, magnesium, and albumin, which require precise wavelength matching for accurate quantitation. Conventional calibration methods using bandpass filters are complex, costly, and prone to errors from instrument-to-instrument variability.
Innovation Solution
A method for calibrating clinical chemistry instruments by measuring and comparing the wavelength band shape and centroid of light emitting diodes (LEDs) to a reference, allowing for the calculation and application of corrections to reflection density or absorbance values, thereby compensating for wavelength variability without the need for bandpass filters, and enabling precise calibration before the instrument is assembled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If precision bandpass filters are employed to control illumination wavelength, then wavelength control is achieved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the wavelength selection function from complex bandpass filters and implements it through a simpler monochromator system using a diffraction grating and selectable exit slits. This removes the need for multiple precision bandpass filters while achieving the same wavelength control function.
Solution Approach 2:
The patent replaces the optical filtering mechanism (bandpass filters) with a monochromator system that uses diffraction and geometric selection. This substitutes a mechanical/optical filtering approach with a diffraction-based wavelength selection mechanism that is less complex.
2Measurement precision
If conventional calibration with real test slides is performed, then instrument calibration is achieved, but time consumption and dependency on test slide quality increase
Solution Approach 1:
The patent performs preliminary characterization of the light source wavelength spectrum before actual calibration. By measuring and storing the wavelength band shape and centroid in advance, the system prepares correction factors that simplify the subsequent calibration process and reduce dependency on test slide quality.
Solution Approach 2:
The patent introduces an intermediary reference measurement system that characterizes the light source independently of test slides. This intermediary step creates correction factors that mediate between the light source variability and the final calibration, reducing the impact of test slide quality variations.
3Manufacturing precision
If bandpass filters are used for wavelength control, then wavelength precision is improved, but instrument downtime for filter replacement increases
Solution Approach 1:
The patent replaces expensive, fragile bandpass filters with a more robust monochromator system using diffraction gratings and mechanical slits. While the individual components may have shorter lifetimes, the system as a whole is more repairable and less prone to catastrophic failure, reducing overall instrument downtime.
Solution Approach 2:
The patent implements a dynamic wavelength selection system using a monochromator with movable slits and rotating grating, replacing static bandpass filters. This dynamic system allows for flexible wavelength adjustment and is more adaptable to maintenance needs, reducing instrument downtime.
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 method improves the consistency and accuracy of measurements across different instruments by accounting for LED wavelength variability, reducing the need for frequent filter replacements and instrument downtime, and providing a more precise calibration process that is less dependent on real test slides.
Implementation Method 1
at least one light emitting diode emits light having a wavelength band shape and a centroid wavelength
Implementation Method 2
The reagent test slide has a reflection density wavelength spectrum associated therewith
Data Source
AI summary
A method of deriving correction for instrument-to-instrument variations in the illumination band centroid wavelengths and wavelength band shapes of the optical systems of clinical chemistry instruments includes the steps of determining the centroid wavelength and wavelength band shape of a light source used in the optical system of a clinical chemistry instrument to provide a determined wavelength band shape and centroid wavelength, comparing the determined wavelength band shape and centroid wavelength with a known reflection density or absorbance wavelength spectrum of a specific type of chemical reagent test to provide a correction value, and calculating the correction value, which is to be used to modify a reflection density or absorbance measurement taken by the instrument of a reagent test of the a specific type of chemical reagent test.