| Reasons for Cancelling | Year | ||||
| 2012 | 2013 | 2014 | 2015 | 2016 | |
| Insufficient material | 19 | 59 | 50 | 84 | 90 |
| Exam not recommended | 26 | 24 | 40 | 16 | 11 |
| Injury not found | 5 | 2 | 0 | 0 | 0 |
| Injury size below 0.5 cm | 18 | 1 | 1 | 0 | 28 |
| Difficulties during collection | 24 | 11 | 8 | 3 | 6 |
| Cancellation by the owner | 0 | 1 | 0 | 0 | 0 |
| Nonviable material received | 0 | 0 | 0 | 3 | 0 |
| Cancellation without justification | 108 | 103 | 77 | 81 | 102 |
| Total | 200 | 201 | 176 | 187 | 237 |