Table 2. Concordance between classification and bone marrow evaluation.

Classification (LDH)		Bone marrow evaluation
		Pathologist 1			Pathologist 2			Pathologist 3			Pathologist 4
		ET	PV	prePMF	ET	PV	prePMF	ET	PV	prePMF	ET	PV	prePMF
ET		6	0	1	6	0	1	3	0	3	1	2	3
preMF		3	0	4	2	0	5	0	2	5	1	2	4

The concordance between the classification and hematopathologist 1, 2, 3, and 4 was 71%, 79%, 62%, and 38%. Three bone marrow biopsies were not suitable for analysis and therefore excluded from the study. Furthermore, pathologist 3 and 4 classified one of the ET bone marrow biopsies as unsuitable. In total, 14 bone marrow biopsies were evaluated by pathologist 1 and 2, and 13 bone marrow biopsies were evaluated by pathologist 3 and 4.