1. Results Interpretation and Database Management
Module 7:
Xpert MTB/RIF
Results Interpretation and Database Management
Global Laboratory Initiative – Xpert MTB/RIF Training Package

2. Contents of this module
Visualizing test results
Reasons to repeat a test
Generating reports

3. Learning objectives At the end of this module, you will be able to:
Analyse the different possible results displayed by the software
Describe the reasons for repeating the test
Generate reports

4. Visualizing the test results
Click on “VIEW RESULTS”
To visualize one particular result, click on «VIEW TEST»

5. Visualizing the test results (contd.)
«VIEW TEST»: Double click on the test you want to see

6. Visualizing the test results (contd. – 2)
Information about test
Interpretation of results
Real-Time PCR curves

7. Edit test-related information of the test result
If necessary you can edit the test related information and notes after the end of test of while it’s running
1. All the white fields in this section are editable
2. After editing click on “Save Changes”

8. Edit test-related information of the test result (contd.)
3. Click “Yes” to confirm the changes
4. The history of the changed information is saved under the tab “History”

9. MTB not detected: Negative Result

10. MTB detected / RIF resistance not detected

11. MTB detected / RIF resistance detected

12. MTB detected / RIF resistance indeterminate
The concentration of MTB in the sample was very low and resistance could not be determined due to insufficient data collected to interpret resistance-related signals

13. Reasons to repeat the test: Invalid Result
Presence or absence of MTB could not be determined due to:
Sample Processing Control (SPC) did not meet acceptance criteria
Sample was not properly processed
PCR was inhibited

14. Reasons to repeat the test: Error
Probe Check Control failed and the assay was aborted due to:
The reaction tube being filled improperly
A reagent probe integrity problem was detected
The maximum pressure limits were exceeded
A GeneXpert module failure
Specific errors, reasons and remedies are discussed in Module 9

15. Reasons to repeat the assay: No Result
Insufficient data were collected due to:
Power failure
Test stopped by the operator
Etc.

16. Reasons to repeat the assay: RIF resistance indeterminate
Concentration of MTB in the sample was too low to provide sufficient data for interpreting resistance-related signals
Collect and test another sample

17. Understanding the Growth Curves
This slide may be considered optional for trainings of basic users
During PCR amplification, DNA sequences are copied at each cycle
The amount of DNA in the reaction doubles at each cycle, resulting in an exponential amplification of the initial target DNA
The reaction is measured at the log- linear phase of amplification
Plateau
Log-linear
Baseline 17

18. Real-time Growth Curve: Cycle threshold (Ct)
This slide may be considered optional for trainings of basic users
Plateau
Detected
Log-linear
Not detected
Baseline

19. Xpert MTB/RIF Semi-Quantitative Results
This slide may be considered optional for trainings of basic users
Depending on the Ct value of the MTB target, the MTB result is displayed as:
High (less than 16 cycles)
Medium (from 16 to 22 cycles)
Low (from 23 to 28 cycles)
Very Low (more than 28 cycles)

20. Xpert MTB/RIF Semi-Quantitative Results
This slide may be considered optional for trainings of basic users
Ct < 16: MTB detected High
Ct > 28: MTB detected Very Low
Ct 16 – 22: MTB detected Medium
Ct 22 – 28: MTB detected Low
The graph is from

21. Sample Processing Control: passed
This slide may be considered optional for trainings of basic users
Target Negative
SPC Positive
Target Positive
SPC Negative

22. Sample Processing Control: invalid
This slide may be considered optional for trainings of basic users
Result invalid
SPC negative
Target negative

23. Generate a result report
1. Click on “VIEW RESULTS”
2. Click on «REPORT»

24. Generate a result report in pdf
3b. Click on “Preview pdf” for immediate vizualisation
3. Select the result to visualize in the pdf
4. Click on “Generate Report File”

25. Generate a Specimen report in pdf
1. Click Reports -> Specimen Report
3a.“Generate Report File” will save the
report in GeneXpert Folder -> Report
2. Fill in the Sample ID
3.“Preview PDF” will open the pdf file

26. Generate a Patient report in pdf
1. Click Reports -> Patient Report
3a.“Generate Report File” will save the
report in GeneXpert Folder -> Report
2. Fill in the Patient ID
3.“Preview PDF” will open the pdf file

27. How to print automatically a test report
- Connect and install your printer
- NOTE: You can print any report once test is finished
1.Click on ‘’Setup’’, then “System configuration”
2.Select the appropriate option ‘’Print Test Report At End of Test’’
3.Click ‘’OK’’

28. How to copy/paste data to excel
1. Click “Data Management”
2. Click “Archive test”
3. Put the mouse cursor on first
test click and hold the left mouse
Button Drag the mouse down until the
last line *
4. While the lines marked press
Cltr+C at the same time on
your keyboard *

29. How to copy/paste data to excel (contd.)
1. Open MS Excel by clicking
Start -> All Programs ->
Microsoft Office -> Microsoft
Excel 2010
2. Click the right mouse button
and in the menu and choose
“Match destination Formatting”
 click on it – see below
3. The chosen results will be
pasted in excel sheet *

30. Summary
GeneXpert software allows visualization of test results as well as the editing of the test result information and the generation of a printable result reports (by specimen or patient)
Errors, invalid results, no results, and RIF resistance indeterminate results are possible outcomes of tests, which warrant a repeat test to be performed

31. Assessment
List the different results obtainable from an Xpert MTB/RIF test
List the different reasons to repeat an Xpert MTB/RIF test

32. Acknowledgements
The Xpert MTB/RIF Training Package has been developed by a consortium of GLI partners, including FIND, KNCV, US CDC, USAID, TB CARE I and WHO, with funding from USAID.
The modules are based on materials originally developed by FIND, KNCV and Cepheid.