Calibration Verification (Linearity)

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Determine the accuracy of calibration throughout the reportable range using different dilutions of an analytical solution.

CLIA Recommendation: Must be done every 6 months for non-waived quantitative assays calibrated with less than three levels of calibrators.

Number of Levels:   3 4 5 6

Enter Values and Replicates below separated by a comma (e.g. 4,3,6):


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Slope:
Y-intercept:
Coefficient of Determination(r2):
Interpretation:
Verified Range:

Linear Regression Graph
%Bias of Mean versus Target Values

Definition of Terms:

Calibration verification is supposed to be a continuing performance check (at least every 6 months or whenever reagent lots are changed, major preventive maintenance is performed, or control problems persist after corrective actions) on the accuracy of calibration throughout the reportable range.

Formula:

n = Number of points or dilutions
x-axis = target values
y-axis = recovered values
sumxy = sum of the products of the target & recovered values of a certain dilution
sumx = sum of all target values
sumy = sum of all recovered values
sumx2 = sum of all the squares of target values
sumy2 = sum of all the squares of recovered values
slope = ((n * sumxy) – (sumx * sumy))/((n * sumx2) – (sumx ²))
intercept = sumy – (slope * sumx)/n
coefficient of determination = ((n * sumxy) – (sumx * sumy)) / (((n * sumx2) – sumx² * ((n * sumy2) – sumy²)^0.5

Passing Criteria:

• Slope should be between 0.85 and 1.15
• Square of the Coefficient of Determination should be equal or less than 0.95

Please check out our list of calculators for Laboratory Statistics:

• Standard Deviation Calculator from Reference Range
• Standard Deviation Calculator using Data Points
• Calibration Verification and Linearity
• Method Validation and Correlation