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. Author manuscript; available in PMC: 2015 Feb 25.
Published in final edited form as: Clin Lab Med. 2011 Oct 10;31(4):763–784. doi: 10.1016/j.cll.2011.08.005

Table 1.

The Evolving Classification of MDS

FAB 1982 WHO 2001 WHO 2008 Blasts Other Findings Cytogenetic
abnormalities
RA RA RCUD
RA
RN
RT
<1% PB**
<5% BM
Uni or bi-lineage dysplasia*
<15% RS
25%
RARS RARS RARS None in PB, <15% BM At least 15% RS 10%
RCMD
RCMD-RS
RCMD (−RS) <1% PB***
<5% BM
Dysplasia >10% in 2 cell lines, +/−
RS, no AR****
50%
RAEB RAEB-1 RAEB-1 <5% PB
5–9% BM
Cytopenia, <1K/ul mono; dysplasia
in 1 or more lines, no AR****
50–70%
RAEB-2 RAEB-2 5–19%
10–19 BM
Cytopenia, <1K/uL mono, +/− AR;
dysplasia in 1 or more lines
50–70%
MDS-U <1% PB;
<5% BM
Cytopenia, <10% dysplasia;
cytogenetic abnormalities present
50%
MDS with 5q <1% PB
<5% BM
Anemia, nml or incr. platelets,
isolated del(5q), hypo-lobated
megakaryocytes, no AR
100%
RAEB-T 20–29% BM
CMML

Stipulations:

*

If pancytopenia present, change to MDS-U;

**

If 1% blasts present, change to MDS-U;

***

if 2–4% PB blasts present, upgrade to RAEB-1;

****

if AR present, upgrade to RAEB-2.

Abbreviations: FAB, French American British classification; WHO, World Health Organization classification; RA, Refractory Anemia; RARS, Refractory Anemia with Ring Sideroblasts; RAEB, Refractory Anemia with Excess Blasts; RAEB-T, Refractory Anemia with Excess Blasts in Transformation; CMML, Chronic Myelomonocytic Leukemia; AML, Acute Myeloid Leukemia; RCMD, Refractory Cytopenia with Multi-lineage Dysplasia; RCUD, Refractory Cytopenia with Uni-lineage Dysplasia; MDS-U, Myelodysplastic syndrome-unclassified; AR, Auer Rods; PB, peripheral blood; BM, bone marrow; RS, ring sideroblasts (% indicates percent RS of total nucleated erythroid precursors).

Bold text indicates the current classification.