Low PDW (Platelet Distribution Width) occurs when there is insufficient platelet production in the blood or when abnormalities are observed in the size distribution of produced platelets. This condition can be an indicator of various underlying health problems. Primary causes that may lead to low PDW values include bone marrow suppressants like leukemia, radiotherapy, chemotherapy, blood clotting disorders, aplastic anemia, and certain platelet conditions such as thrombocytosis.