IVD EP9A

4.Preliminary Data Examination
4.1 Outlier Tests on Within-Method Duplicates
The source of the problem Can be identified and traced to the offending sample alone Can be corrected but not traced to specific sample Can be neither found nor corrected Replace those sample in the data set
parison of Methods Experiment
3.5 Sample Sequence
First : in forward order ; Second (Duplicate) : in reverse order Minimizes the effects of carryover and drift on the averages of the duplicates within run.
4.Preliminary Data Examination
4.1 Outlier Tests on Within-Method Duplicates
4.Preliminary Data Examination
4.1 Outlier Tests on Within-Method Duplicates
Method Comparison and Bias Estimation Using Patient Sample
主講人:許欽豪 日期:96.02.23
Method Comparison and Bias Estimation Using Patient Sample
Section: 1.Introduction 2.Device-Familiarization Period parison of Methods Experiment 4.Preliminary Data Examination 5.Linear Regression puting Predicted Bias and Its Confidence Interval 7.Interpreting Results 8.Conclusion
1.Introduction
1.3 Symbols used in the test
2.Device-Familiarization Period
2.1 The subcommittee recommends 5 days for the device familiarization period.
parison of Methods Experiment
3.7 Inspection of Data During Collection
Analytic system errors Human error Evaluation of other Discrepant Data
3.8 Quality Control
1.Introduction
1.1 Purpose The document provides both users and manufactures of clinical laboratory devices with guideline to evaluate the bias between two methods that measure the same analyte. 1.2 Overview of Comparison Exp. (1) Familiar with the device's operation and maintenance procedures. (2) Familiar with the evaluation protocol. (3) Both the test and the comparative methods are in proper quality control.
parison of Methods Experiment
parison of Methods Experiment
3.4 Number of Specimens
At least 40 specimens Duplicate measurement Pooled specimens if not enough volume from single patient ( mixed from two patients but not more )
4.Preliminary Data Examination
4.2 Plotting the Data ( 4 plots )
individual Y against mean X
4.Preliminary Data Examination
4.2 Plotting the Data ( 4 plots )
4.Preliminary Data Examination
4.1 Outlier Tests on Within-Method Duplicates
Single point falls outside the limits More than one outside the limits Analyze the data set after deleting this point 1.Delete those data 2.Investigate the cause of the problem 3.The cause of the problem must be documented
3.6 Time and Duration
Analysis by both methods within 2 hrs Comparison exp after precision exp Comparison and precision exp the same time 8 specimens/day 4 specimens/day
4.1 Outlier Tests on Within-Method Duplicates
normalized ( relative ) absolute difference ( if any individual absolute difference exceeds the appropriate limit )
Entire data set must be recollected Evaluate the maximum difference between duplicates relative to the allowable medical decision limits. If those limits are not exceeded, follow the next step. If those limits are exceeded, stop the exp. and notify the manufacturer.
1.Introduction
(4) Sufficient data to ensure representative results for both methods.
at least 40 patient samples at least 5 operating days at least 50% of samples run should be outside the Lab's reference interval
4.Preliminary Data Examination
4.3 Visual Check for Linear Relationship
Satisfactory linear relationship , follow next step ( section 4.4 ) Nonlinear relationship (1) Generally nonlinearity will occur at the extremes values. (2) Examine the remaining linear portion to determine whether it is sufficiently wide to cover the medical range. (3) Analyze additional samples within that range to replace these excluded samples. (4) Examine the new data set beginning again at section 4 (5) If no linear portion is evident, stop the evaluation and notify the manufacturer.
parison of Methods Experiment
3.1 Test Specimens
Storage : stability of the constituent ; avoid storing specimens if possible Source : Do not use samples with conditions (e.g. hemolysis) that are known to interfere with either method.
Bias ( mean Y and mean X difference) versus mean X
4.Preliminary Data Examination
4.2 Plotting the Data ( 4 plots )
Bias ( individual Y and X difference) versus mean X