| Items | Breakdown | Cases (n = 141) | % |
| Medical Examination | Mistake of specimen collection | 23 | 16.3 |
| Mistake of specimen | 9 | 6.4 | |
| Mistake of correct patients | 8 | 5.7 | |
| Mistake of laboratory technique and judgement technique | 6 | 4.3 | |
| Report of results | 5 | 3.5 | |
| Laboratory equipment, preparation of medical instrument | 3 | 2.1 | |
| Damage of specimen | 3 | 2.1 | |
| Contamination of specimen | 2 | 1.4 | |
| Mistake of data management | 2 | 1.4 | |
| Management of reagent | 1 | 0.7 | |
| Calculation, inputting, memorizing | 0 | 0.0 | |
| Management of analytical instrument and laboratory equipment | 0 | 0.0 | |
| Others | 79 | 56.0 |