passing & bablok and deming regression · 2019-09-20 · loa . bland-altman plot mean...
TRANSCRIPT
![Page 1: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/1.jpg)
PASSING & BABLOK AND DEMING REGRESSION
Vanja Radišić Biljak
Department of medical laboratory diagnostics, University Hospital „Sveti Duh”, Zagreb, Croatia
![Page 2: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/2.jpg)
PASSING & BABLOK AND DEMING REGRESSION
BLAND & ALTMAN PLOT
Vanja Radišić Biljak
Department of medical laboratory diagnostics, University Hospital „Sveti Duh”, Zagreb, Croatia
![Page 3: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/3.jpg)
METHOD COMPARISON
Vanja Radišić Biljak
Department of medical laboratory diagnostics, University Hospital „Sveti Duh”, Zagreb, Croatia
![Page 4: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/4.jpg)
Method verification
• Confirming that declared test specifications can be
achieved in the clinical laboratory
• Precision
• Accuracy
• Linearity
• Interferences
• LOD, LOQ...
• Method comparison
![Page 5: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/5.jpg)
When and why?
Introducing new method or analyzer
Multiple analytical systems in laboratory
Using services of another laboratory
Method change is not going to influence
laboratory result for the patient
![Page 6: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/6.jpg)
How?
• Experimental procedures following protocols
• CLSI EP09-A3: Measurement procedure comparison and
bias estimation using patient samples
1. Number of samples
2. Measurement range
3. Time of analysis
4. Data analysis
5. Data interpretation
![Page 7: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/7.jpg)
Number of samples
• Min: 40 samples
• Optimal: 100 samples • To identify unexpected errors from sample matrix or
interferences
• Measurements in duplicate: use mean value
• Measurements in triplicate: use median value
![Page 8: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/8.jpg)
Measurement range
• Cover 90% of the method measurement range
Method A
Method B
Measurement range
Good
agreement
between
methods Difference in
higher
concentration
range
![Page 9: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/9.jpg)
Measurement range
• Overlaping measurement range for both methods
Glucose
concentration
Method A
Method B
Method A using
dilution protocol
Method B
reported as
LOQ
![Page 10: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/10.jpg)
Data analysis
Several statistical aproaches:
•Correlation
•Paired test for difference
•Bland-Altman analysis
•Linear regression
• Deming regression
• Passing-Bablok regresion
![Page 11: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/11.jpg)
![Page 12: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/12.jpg)
Data analysis
Several statistical aproaches:
•Correlation
•Paired test for difference
•Bland-Altman analysis
•Linear regression
• Deming regression
• Passing-Bablok regresion
![Page 13: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/13.jpg)
Analyzing results
• Comparison of two methods for testosterone
concentration measurement
Summary data
nmol/L Method 1
N=122
Method 2
N=122
Analyzer E411
(Roche)
Architect 1000i
(Abbott)
Min-Max 0.297 – 3.34 0.78 – 2.83
Mean ± SD 1.38 ± 0.50 1.43 ± 0.38
Median (IQR) 1.33 (0.99 – 1.69) 1.38 (1.15 – 1.63)
P (normality) <0.001
REJECTED
<0.001
REJECTED
![Page 14: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/14.jpg)
Scatter plot
![Page 15: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/15.jpg)
Analyzing results
• Comparison of two methods for testosterone
concentration measurement
Summary data
nmol/L
Method 1
N=122
Method 2
N=122
Analyzer E411
(Roche)
Architect 1000i
(Abbott)
Min-Max 0.297 – 3.34 0.78 – 2.83
Mean ± SD 1.38 ± 0.50 1.43 ± 0.38
Median (IQR) 1.33 (0.99 – 1.69) 1.38 (1.15 – 1.63)
P (normality) <0.001
REJECTED
<0.001
REJECTED
![Page 16: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/16.jpg)
Types of correlation
• Pearson (rp) and Spearman correlation (rs)
122 samples < 30 Spearman
correlation
Numerical data At least one
ordinal data
Spearman
correlation
Reject normality
Both variables
do not follow
normal
distribution
Spearman
correlation
Pearson correlation
![Page 17: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/17.jpg)
Correlation
• Spearman coefficient of correlation
![Page 18: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/18.jpg)
Coefficient of correlation (r)
Coefficient of
correlation (r) Interpretation
0-0.24 No association
0.25-0.49 Poor association
0.50-0.74 Moderate to good
association
0.75-1.00 Very good to excellent
association
r can be interpreted only if P < level of significance (0.05)
![Page 19: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/19.jpg)
What is the meaning of this result?
• Methods are significantly associated
• Linear relation between methods
• ↑ of Method A associated with ↑ of Method B
• Nothing about interchangeability of
methods!
WHY?
![Page 20: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/20.jpg)
Example 1
r (95% CI) =
1.00 (1.00-1.00)
Method 2 =
Method 1 + 10
Method 2 = Method 1
![Page 21: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/21.jpg)
Example 2
r (95% CI) =
1.00 (1.00-1.00)
Method 3 =
1,5 x Method 1
Method 2 = Method 1
![Page 22: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/22.jpg)
Example 3
r (95% CI) =
1.00 (1.00-1.00)
Method 4 =
1,5 x Method 1 + 20
Method 2 = Method 1
![Page 23: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/23.jpg)
Data analysis
Several statistical aproaches:
•Correlation
•Paired test for difference
•Bland-Altman analysis
•Linear regression
• Deming regression
• Passing-Bablok regresion
![Page 24: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/24.jpg)
Data analysis
Several statistical aproaches:
•Correlation
•Paired test for difference
•Bland-Altman analysis
•Linear regression
• Deming regression
• Passing-Bablok regresion
![Page 25: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/25.jpg)
Analyzing results
• Comparison of two methods for testosterone
concentration measurement
Summary data
nmol/L
Method 1
N=122
Method 2
N=122
Analyzer E411
(Roche)
Architect 1000i
(Abbott)
Min-Max 0.297 – 3.34 0.78 – 2.83
Mean ± SD 1.38 ± 0.50 1.43 ± 0.38
Median (IQR) 1.33 (0.99 – 1.69) 1.38 (1.15 – 1.63)
P (normality) <0.001
REJECTED
<0.001
REJECTED
![Page 26: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/26.jpg)
Significance of difference
• Wilcoxon test (normality failed)
P=0.02
![Page 27: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/27.jpg)
Significance of difference
• Wilcoxon test (normality failed)
P=0.02
Significant
difference between
methods
![Page 28: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/28.jpg)
What is the meaning of this result?
• Calculating differences for each pair of measurement
• Comparing number of negative and positive differences
• If there is no difference between methods, number of
differences is equal
More measurements were higher using Method 2
![Page 29: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/29.jpg)
Data analysis
Several statistical aproaches:
•Correlation
•Paired test for difference
•Bland-Altman analysis
•Linear regression
• Deming regression
• Passing-Bablok regresion
![Page 30: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/30.jpg)
Data analysis
Several statistical aproaches:
•Correlation
•Paired test for difference
•Bland-Altman analysis
•Linear regression
• Deming regression
• Passing-Bablok regresion
![Page 31: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/31.jpg)
Bland-Altman analysis
• Graphical method to compare two measurements
technique
• Analyzing differences between measurement pairs
• Identification of constant and proportional bias
Giavarina D. Understanding Bland Altman analysis. Biochem Med (Zagreb) 2015;25(2):141-51.
![Page 32: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/32.jpg)
Calculating differences
Average = - 0.05
Ideal situation: all differences = 0
Real situation (analytical
variability): all differences
close to 0 (some +; some -)
The average of all calculated
differences between measurement
pairs close to 0
![Page 33: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/33.jpg)
Bland-Altman plot
Mean difference
Mean of methods
Diffe
rence
0
+1.96 s
LOA
First method or
Reference method
(true value)
Laboratory methods
(no true value)
95% CI
95% CI
-1.96 s
LOA
![Page 34: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/34.jpg)
Bland-Altman plot
Mean difference
Mean of methods
Diffe
rence
0
+1.96 s
LOA
First method or
Reference method
(true value)
Laboratory methods
(no true value)
95% CI
95% CI
-1.96 s
LOA
![Page 35: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/35.jpg)
Evaluating difference
Mean difference
Mean of methods
Diffe
rence
0
+1.96 s
LOA
95% CI
95% CI
-1.96 s
LOA
95% CI Including 0
No statistically significant
difference
![Page 36: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/36.jpg)
Evaluating difference
Mean difference
Mean of methods
Diffe
rence
0
+1.96 s
LOA
95% CI
95% CI
-1.96 s
LOA
95% CI Excluding 0
Statistically significant
difference
![Page 37: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/37.jpg)
Type of difference
Mean difference
Mean of methods
Diffe
rence in m
easure
ment
units
Meth
od 2
– M
eth
od 1
0
+1.96 s
LOA
95% CI
95% CI
-1.96 s
LOA
Evaluating
constant bias
![Page 38: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/38.jpg)
Type of difference
Mean difference
Mean of methods
Diffe
rence in p
erc
enta
ges
(Me
thod 2
– M
eth
od 1
)/M
eth
od 1
x100%
0
+1.96 s
LOA
95% CI
95% CI
-1.96 s
LOA
Evaluating
proportional
bias
![Page 39: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/39.jpg)
Limits of agreement
Normal distribution → 95% cases within ± 1.96 s
![Page 40: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/40.jpg)
Limits of agreement
Mean difference
Mean of methods
Diffe
rence
0
+1.96 s
LOA
95% CI
95% CI
-1.96 s
LOA
95% of the
differences within
LOA
![Page 41: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/41.jpg)
Limits of agreement
Mean difference
Mean of methods
Diffe
rence
0
+1.96 s
LOA
95% CI
95% CI
-1.96 s
LOA
Narrow LOA
Good agreement
Wide LOA
Poor agreement
![Page 42: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/42.jpg)
Precision of limits of
agreement
Mean difference
Mean of methods
Diffe
rence
0
+1.96 s
LOA
95% CI
95% CI
-1.96 s
LOA
95% CI of limits of
agreement
![Page 43: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/43.jpg)
Distribution of differences – Mountain plot
![Page 44: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/44.jpg)
Distribution of differences – Mountain plot
P = 0.097
Normality accepted
![Page 45: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/45.jpg)
Distribution of differences – Mountain plot
P = 0.097
Normality accepted
How are differences
distributed
according to
concentration level?
![Page 46: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/46.jpg)
Distribution of differences – Mountain plot
P = 0.097
Normality accepted
How are differences
distributed
according to
concentration level?
Bland-Altman
plot
![Page 47: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/47.jpg)
![Page 48: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/48.jpg)
![Page 49: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/49.jpg)
Testosterone comparison (1)
1) Mean difference -0.05 mmol/L
2) Difference statistically
significant
3) Constant bias
4) Shape of the cloud
indicates aditional
proportional bias
![Page 50: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/50.jpg)
![Page 51: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/51.jpg)
![Page 52: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/52.jpg)
Testosterone comparison (2)
1) Mean difference -0.05 mmol/L
2) Difference statistically
significant
3) Constant bias
4) Shape of the cloud
indicates aditional
proportional bias
![Page 53: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/53.jpg)
![Page 54: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/54.jpg)
Testosterone comparison (3)
1) Mean difference -6.9%
2) Difference statistically
significant
3) Proportional bias
![Page 55: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/55.jpg)
Testosterone comparison (4)
1) Mean difference -6.9%
2) Difference statistically
significant
3) Proportional bias Is this difference clinically significant?
![Page 56: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/56.jpg)
Data interpretation
Statistical significance Clinical significance
Comparing values
with predefined
acceptance
criteria
![Page 57: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/57.jpg)
https://www.westgard.com/biodatabase1.htm
![Page 58: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/58.jpg)
Testosterone comparison (5)
13,6%
allowed
TE
![Page 59: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/59.jpg)
https://biologicalvariation.eu
BA = 0.25 (CVI2 + CVG
2)1/2
![Page 60: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/60.jpg)
Testosterone comparison (6)
Summary data
nmol/L
Method 1
N=122
Method 2
N=122
Reference
method
Analyzer E411 (Roche) Architect 1000i
(Abbott)
LCMS
Min-Max 0.30 – 3.34 0.78 – 2.83 0.54 – 2.43
Mean ± SD 1.38 ± 0.50 1.43 ± 0.38 1.22 ± 0.39
Median (IQR) 1.33
(0.99 – 1.69)
1.38
(1.15 – 1.63)
1.15
(0.94 – 1.42)
P (normality) <0.001
REJECTED
<0.001
REJECTED
<0.001
REJECTED
![Page 61: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/61.jpg)
Bland-Altman plot
Mean difference
Mean of methods
Diffe
rence
0
+1.96 s
LOA
First method or
Reference method
(true value)
Laboratory methods
(no true value)
95% CI
95% CI
-1.96 s
LOA
![Page 62: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/62.jpg)
Testosterone comparison (6)
![Page 63: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/63.jpg)
Data analysis
Several statistical aproaches:
•Correlation
•Paired test for difference
•Bland-Altman analysis
•Linear regression
• Deming regression
• Passing-Bablok regresion
![Page 64: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/64.jpg)
Data analysis
Several statistical aproaches:
•Correlation
•Paired test for difference
•Bland-Altman analysis
•Linear regression
• Deming regression
• Passing-Bablok regresion
![Page 65: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/65.jpg)
Linear regression
High correlation
Linear relationship
Equation to describe relationship
between methods
Determine proportional and constant error
Deming regression
Passing and Bablok regression
Bilić-Zulle L. Comparison of methods: Passing and Bablok regression. Biochem Med (Zagreb) 2011;21:49-52.
![Page 66: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/66.jpg)
Linear regression
Regression equation
y = a + bx
Intercept = a
tg (α) = b
x
y
Method B
α
Method A
95% confidence
intervals y = x
Regression equation
y = a (95% CI) +
b (95% CI) x
![Page 67: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/67.jpg)
Constant and proportional error
Intercept = a
tg (α) = b
x
y
Method B
α
Method A
Regression equation
y = a (95% CI) + b (95% CI) x
Excluding 0
Constant
error
y = x Excluding 1
Proportional
error
![Page 68: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/68.jpg)
Deming regression
• Includes analytical variability of both methods (CV)
• Both methods prone to errors (clinical laboratory)
There are limitations to using Deming regression!!!
Assumes that errors are independent and normally distributed!
Sensitive to outliers!
![Page 69: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/69.jpg)
Testosterone comparison (7)
![Page 70: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/70.jpg)
Testosterone comparison (7)
![Page 71: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/71.jpg)
Testosterone comparison (7)
y = 0.44 (0.36 to 0.52) + 0.72 (0.65 to 0.78) x
Constant bias Proportional difference
![Page 72: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/72.jpg)
Why don’t we recalculate results?
Testo (Architect) = 0.44+ 0.72 x Testo (e411)
Testo (e411) = (Testo (Architect) – 0.44) / 0.72
![Page 73: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/73.jpg)
Residual analysis
• Calculation of the results using the regression equation
• Calculation of the difference between calculated and
measured value
![Page 74: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/74.jpg)
Residual analysis
y
x
Y – F(x)
0
> 0
< 0
All measuremets near the regression line Difference between actual Y and
calculated Y close to 0
Good fit; equation can be used
![Page 75: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/75.jpg)
Residual analysis
x
y
x0
> 0
< 0
Many measuremets far from the regression line Difference between actual Y and
calculated Y different than 0
Poor fit; equation can’t be used
![Page 76: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/76.jpg)
Residual analysis
Differences between measured and calculated values
![Page 77: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/77.jpg)
Passing & Bablok regression
• Non-parametric method
• No assumptions about distributions of samples
• No assumptions about distributions of errors
• Not sensitive to outliers
Confirming linear relation between methods
If linearity test failed, Passing Bablok regression should not be used!
![Page 78: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/78.jpg)
Testosterone comparison (8)
Deming regression
y = 0.44 (0.36 to 0.52) +
0.72 (0.65 to 0.78) x
Passing & Bablok
regression
y = 0.42 (0.35 to 0.50) +
0.73 (0.66 to 0.80) x
![Page 79: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/79.jpg)
![Page 80: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/80.jpg)
Data analysis
Several statistical aproaches:
•Correlation
•Paired test for difference
•Bland-Altman analysis
•Linear regression
• Deming regression
• Passing-Bablok regresion
![Page 81: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/81.jpg)
Some examples…
Summary data
RBC
1012/L
Analyzer 1
N=300
Analyzer 2
N=300
Min-Max 1.82 – 7.15 1.82 – 7.24
Mean ± SD 4.49 ± 0.84 4.56 ± 0.85
Median (IQR) 4.50 (4.07 – 5.01) 4.58 (4.17 – 5.05)
P (normality) 0.01
REJECTED
<0.001
REJECTED
![Page 82: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/82.jpg)
Some examples…
![Page 83: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/83.jpg)
Some examples…
![Page 84: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/84.jpg)
Some examples…
![Page 85: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/85.jpg)
Some examples…
No constant nor
proportional differences
![Page 86: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/86.jpg)
Some examples…
Summary data
HGB
g/L
Analyzer 1
N=300
Analyzer 2
N=300
Min-Max 66 – 243 64 – 245
Mean ± SD 135 ± 27 134.7 ± 26
Median (IQR) 135 (121 – 149) 135 (121.5 – 148)
P (normality) <0.001
REJECTED
<0.001
REJECTED
![Page 87: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/87.jpg)
Some examples…
![Page 88: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/88.jpg)
Some examples…
![Page 89: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/89.jpg)
Some examples…
![Page 90: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/90.jpg)
Some examples…
![Page 91: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/91.jpg)
Some examples…
![Page 92: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/92.jpg)
Some examples…
If linearity test failed, Passing Bablok regression should not be used!
![Page 93: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/93.jpg)
What to do?
![Page 94: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/94.jpg)
CLSI EP09-A3
![Page 95: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/95.jpg)
CLSI EP09-A3
![Page 96: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/96.jpg)
Some examples…
Summary data
PLT
109/L
Analyzer 1
N=300
Analyzer 2
N=300
Min-Max 8 – 1693 8 – 1566
Mean ± SD 248 ± 192 231 ± 178
Median (IQR) 215 (113 – 325) 201 (106 – 302)
P (normality) <0.001
REJECTED
<0.001
REJECTED
![Page 97: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/97.jpg)
Some examples…
![Page 98: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/98.jpg)
Some examples…
Proportional error
0 500 1000 1500 2000
0
200
400
600
800
1000
1200
1400
1600
1800
TRC-S
TR
C-N
![Page 99: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/99.jpg)
Method comparison
• Important laboratory procedure for verification
• Included into validation protocols for new reagents
• Comparison with the reference method
• Comparison with different manufacturers
• Comparison with same manufacturer
• Results are presented in manufacturers declarations
![Page 100: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/100.jpg)
P values missing
95%CI missing
Small number of
samples
![Page 101: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/101.jpg)
P values missing
95%CI missing
![Page 102: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/102.jpg)
P values missing
95%CI missing
![Page 103: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/103.jpg)
P values missing
95%CI missing
![Page 104: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/104.jpg)
P values missing
95%CI missing
![Page 105: PASSING & BABLOK AND DEMING REGRESSION · 2019-09-20 · LOA . Bland-Altman plot Mean difference Mean of methods ference 0 +1.96 s LOA First method or Reference method (true value)](https://reader033.vdocuments.site/reader033/viewer/2022042406/5f20dd4f7d9b224e3f4e9aed/html5/thumbnails/105.jpg)
THE END