Assessment of interobserver reliability for bone marrow histology criteria
| Criterion . | Strength of association* . | 95% CI . |
|---|---|---|
| Myelofibrosis criteria (5-point scale) | ||
| WHO diagnosis | 2.1 | 1.8-2.4 |
| Reticulin grade | 5.1 | 4.0-6.4 |
| Cellularity criteria (3-point scale) | ||
| Overall | 8.3 | 5.5-12.6 |
| Erythroid | 3.9 | 2.8-5.3 |
| Granulocytic | 5.0 | 3.4-7.2 |
| Megakaryocytic† | 5.1 | 4.0-6.4 |
| Megakaryocyte morphology (3-point scale) | ||
| Staghorn megakaryocytes | 2.5 | 1.9-3.3 |
| Cloud-like megakaryocytes | 2.2 | 1.7-2.8 |
| Dysplastic megakaryocytes | 1.4 | 1.1-1.7 |
| Pyknotic megakaryocytes | 3.2 | 2.4-4.2 |
| Bare megakaryocyte nuclei | 7.7 | 4.3-13.6 |
| Megakaryocyte size | 3.2 | 2.3-4.5 |
| Megakaryocyte clustering (3-point scale) | ||
| Number of clusters | 9.1 | 6.0-13.9 |
| Type of clusters (none, loose, tight) | 2.7 | 2.2-3.3 |
| Size of clusters (none, small, large) | 6.8 | 4.7-9.7 |
| Miscellaneous (2-point scale) | ||
| Paratrabecular megakaryocytes | 4.4 | 3.1-6.1 |
| New bone formation | 10.1 | 4.8-21.8 |
| Criterion . | Strength of association* . | 95% CI . |
|---|---|---|
| Myelofibrosis criteria (5-point scale) | ||
| WHO diagnosis | 2.1 | 1.8-2.4 |
| Reticulin grade | 5.1 | 4.0-6.4 |
| Cellularity criteria (3-point scale) | ||
| Overall | 8.3 | 5.5-12.6 |
| Erythroid | 3.9 | 2.8-5.3 |
| Granulocytic | 5.0 | 3.4-7.2 |
| Megakaryocytic† | 5.1 | 4.0-6.4 |
| Megakaryocyte morphology (3-point scale) | ||
| Staghorn megakaryocytes | 2.5 | 1.9-3.3 |
| Cloud-like megakaryocytes | 2.2 | 1.7-2.8 |
| Dysplastic megakaryocytes | 1.4 | 1.1-1.7 |
| Pyknotic megakaryocytes | 3.2 | 2.4-4.2 |
| Bare megakaryocyte nuclei | 7.7 | 4.3-13.6 |
| Megakaryocyte size | 3.2 | 2.3-4.5 |
| Megakaryocyte clustering (3-point scale) | ||
| Number of clusters | 9.1 | 6.0-13.9 |
| Type of clusters (none, loose, tight) | 2.7 | 2.2-3.3 |
| Size of clusters (none, small, large) | 6.8 | 4.7-9.7 |
| Miscellaneous (2-point scale) | ||
| Paratrabecular megakaryocytes | 4.4 | 3.1-6.1 |
| New bone formation | 10.1 | 4.8-21.8 |
*Higher scores for strength of association represent stronger interobserver reliability, with a score of 1 indicating no agreement beyond chance.
†The categories of normal (score = 0) and mildly increased (score = 1) were combined because of small numbers in the normal category and to allow comparison with the other criteria for cellularity (all on a 3-point scale).