It is possible that you have not detected the LH surge for several reasons:

1. you started testing too late and missed your surge
2. the tests were not performed correctly
3. you did not ovulate that month (this is called anovulation). If this occurs, try testing daily again the following month, but this time start the testing a couple of days sooner in your cycle
   

Please ensure you are following the instructions carefully, and continue testing until an LH surge is detected. If you are concerned that you still have not been able to detect your LH surge, seek medical advice.