Karyotype, bone marrow blast percentage and cytopenia influence the prognosis of 
myelodysplastic syndrome. We studied the abnormalities detected by fluorescence 
in situ hybridization (FISH) in myelodysplastic syndrome and associated 
haematological profile with abnormalities detected by FISH. Complete blood 
counts, peripheral blood and bone marrow of patients were evaluated for 
cytopenia, dysplasia and blasts. FISH probes were used to detect del(5q), gain 
of chromosome 8, de (7q/-7) and del(20 q). Multiple regression analysis was used 
to study the association of FISH abnormalities, age and sex with haematological 
profile. Mc Nemar's test studied the relationship between FISH abnormalities and 
dysplastic features in bone marrow. Cytogenetic abnormalities were detected by 
FISH in 25.7% of patients. Del(20 q) was seen in 14.2% of patients. FISH was 
able to predict changes in peripheral blood blast count by 80% (p ˂ 0.0001). 
Cytogenetic abnormalities were not seen in 74.2% of patients. Groups with FISH 
abnormalities have a different haematological profile, and these abnormalities 
have a significant effect on blast percentage.