1. Investigating Out of Specification Results
Fiona McGuinness
If you want to remove slide numbering follow these steps:
View
Master view - Slide master
Master layout - Remove tick on Footer

2. Introduction
What do we mean by OOS, OOT, atypical or unexpected results?
Documented procedure
Investigation
What happens when you can’t find the cause?
Examples
Questions

3. What do we mean…? Out of Specification (OOS) Out of trend (OOT)
Result that does not comply with stated accepted criteria
Out of trend (OOT)
A stability result that does not follow the trend of other stability results during a stability study
A result that does not follow the trend based on data already collected with the same compound
Atypical
May be within specification but unexpected or questionable
All unexpected results!

4. Documented Procedure
Important that all laboratories have a fully documented OOS investigation procedure
Clearly state what the investigation will be based on, what you will do in each case, actions and outcomes from the investigation
Clients and regulatory agencies like to see a procedure and that it is being followed!

5. Initial Investigation
First step is to QC Check the data generated to ensure that no identifiable calculation or preparation errors have been made
Investigate the analysis….
Calibration standards, extraction volumes, dilution steps etc
Instrument set-up, injection volumes, mobile phases, diluents, instrument working…

6. Re-dilution An investigative run
Has a dilution error been made?
What if dilution results are different?
Don’t cherry pick results!
Confirm results by a 3rd dilution!

7. Preparation of the Formulation
Check the request, method, weights of test substance and vehicle as appropriate.
Check calculations

8. Contingency Analysis
No obvious analytical error (including dilutions), no obvious preparation error…
Perform analysis of contingency samples

9. What happens when we can’t find the cause of an unexpected result?
Meeting
Root Cause Analysis investigation
Corrective and Preventative Actions
Analysis of next formulated occasion
Discussion and agreement with senior members of department and SD

10. Fishbone

11. 5 Whys

12. Analysed concentration (mg/ml)
Example 1
Week of Formulation
Group
Nominal
Analysed concentration (mg/ml)
RME
% Difference from Mean
inclusion
Analysis 1
Analysis 2
Mean
(%)
(mg/ml) 13 1 ND - 2
0.75
2.6904
2.734
2.71
261.3
-0.80
0.80 3
1.5
1.4978
1.5041
1.50
0.0
-0.21
0.21 4
2.75
0.61
-77.7
0.83
-0.83
Group 2 samples are above the quantification range
Group 4 samples are below the quantification range
Obvious error?

13. Investigation
Samples had been booked into the department in the wrong order
Analyst followed the booking in rather than looking at the labels of the samples
New samples were taken from the bulk sample provided by Pharmacy

14. Analysed concentration (mg/ml)
Re-sampled Analysis
Week of Formulation
Group
Nominal
Analysed concentration (mg/ml)
RME
% Difference from Mean
inclusion
Analysis 1
Analysis 2
Mean
(%)
(mg/ml) 13 1 ND - 2
0.75
0.720
-4.0
0.53
-0.53 3
1.5
1.4978
1.5041
1.50
0.0
-0.21
0.21 4
2.75
2.7186
2.5703
2.64
2.80
-2.80
All samples now within specification
Original results for Groups 2 and 4 not reported due to an identified analyst error

15. Analysed concentration (mg/ml)
Example 2
Week of Formulation
Group
Nominal
Analysed concentration (mg/ml)
RME
% Difference from Mean
inclusion
Analysis 1
Analysis 2
Mean
(%)
(mg/ml) 1 ND - 2 10
9.6428
8.1326
8.89
-11.1
8.50
-8.50 3 30
27.686
26.675
27.2
-9.3
1.86
-1.86 4 60
58.827
57.72
58.3
-2.8
0.95
-0.95
Investigation shows no calculation errors
Re-dilution confirms the results
No preparation errors found with formulation preparation

16. Analysed concentration (mg/ml)
Contingency Analysis
Week of Formulation
Group
Nominal
Analysed concentration (mg/ml)
RME
Precision
% Difference from Mean
inclusion
Analysis 1
Analysis 2
Mean
(%)
from mean
(mg/ml) 1
2 cont 10
9.9601
10.022
9.99
-0.1
0.44
-0.31
0.31
Contingency analysis showed that results were acceptable
What should we do about the original analysis?
Outlier test?

17. Outlier Test – Dixon’s Q Testn 3 4 5 6 7 8 9 10
Q90%
0.941
0.765
0.642
0.560
0.507
0.468
0.437
0.412
Q95%
0.970
0.829
0.710
0.625
0.568
0.526
0.493
0.466
Q99%
0.994
0.926
0.821
0.740
0.680
0.634
0.598

18. Analysed concentration (mg/ml)
Reportable Results
mg/mL was rejected from the mean as an outlier with 90% confidence.
Group
Nominal
Analysed concentration (mg/ml)
RME
Precision
% Difference from Mean
inclusion 1 2 3 4
Mean
(%)
from mean
(mg/ml) 10
9.6428
[8.1326]
9.9601
10.022
9.87
-1.3
2.06
-2.35 -
0.86
1.49

19. Example 3 UV Method – controls usually reportable as <LOQ
One sample (from 3) showed a response >LOQ
Full spectrum scan did not show a test item response
No dilutions available to re-read
Time sensitive as pre-dose analysis!

20. Contingency analysis The next 3 samples were read <LOQ
Full scans were done of all controls = clear of test item response
Rejected the initial sample result as anomalous as 5/6 controls were <LOQ
Full investigation was not required as able to demonstrate the control group was clear by full spectrum scans (of all controls) and results of 5/6 controls

21. Any Questions?