Table 1.

Diagnostic criteria for MDS entities

Name	Dysplastic lineages	Cytopenias	RS (%)*	BM and PB blasts (%)	Cytogenetics†
MDS-SLD	1	1 or 2	<15/<5‡	BM <5, PB <1, no Auer rods	Any, unless fulfills all criteria for MDS with isolated del(5q)
MDS-MLD	2 or 3	1-3	<15/<5‡	BM <5, PB <1, no Auer rods	Any, unless fulfills all criteria for MDS with isolated del(5q)
MDS-RS
MDS-RS-SLD	1	1 or 2	≥15/≥5‡	BM < 5, PB <1, no Auer rods	Any, unless fulfills all criteria for MDS with isolated del(5q)
MDS-RS-MLD	2 or 3	1-3	≥15/≥5‡	BM <5, PB <1, no Auer rods	Any, unless fulfills all criteria for MDS with isolated del(5q)
MDS with isolated del(5q)	1-3	1-2	None or any	BM <5, PB <1, no Auer rods	Del(5q) alone or with 1 additional abnormality except −7 or del(7q)
MDS-EB
MDS-EB-1	0-3	1-3	None or any	BM 5-9 or PB 2-4, no Auer rods	Any
MDS-EB-2	0-3	1-3	None or any	BM 10-19 or PB 5-19 or Auer rods	Any
MDS-U
1% blood blasts	1-3	1-3	None or any	BM <5, PB = 1,§ no Auer rods	Any
SLD and pancytopenia	1	3	None or any	BM <5, PB <1, no Auer rods	Any
Defining cytogenetic abnormality	0	1-3	<15||	BM <5, PB <1, no Auer rods	MDS-defining abnormality
Refractory cytopenia of childhood	1-3	1-3	None	BM <5, PB <2	Any

BM, bone marrow; MDS-EB, MDS with excess blasts; MDS-U, MDS, unclassifiable; PB, peripheral blood.

^*RS as percentage of marrow erythroid elements.

^†Cytogenetics by conventional karyotype analysis.

^‡If SF3B1 mutation is present.

^§One percent PB blasts must be recorded on ≥2 separate occasions.

^||Cases with ≥15% RS by definition have significant erythroid dysplasia and are classified as MDS-RS-SLD.