CHIP ICUS CCUS- pre MDS states

 When cytopenias do not meet criteria for MDS and have only mild dysplasia to none, or < 5 % blasts:

1. If cytopenias: differentiate between CCUS ( MDS mutation) and ICUS ( no dysplasia or mild, no MDS mutation)

2. No cytopenia but with either MDS mutation (CHIP) or dysplasia (IDUS)

• Cytopenia+ MDS mutation--> CCUS
• No cytopenia +MDS mutation-->CHIP

Reference

Pre-MDS	Major diagnostic features and criteria
ICUS	Peripheral cytopenia(s) a , MDS criteria not fulfilled, no MDS-related mutation b found, no or only mild (<10%) dysplasia, blast cells <5% c
CCUS	Peripheral cytopenia(s) a , MDS criteria not fulfilled, one or more MDS-related mutations b found, no or only mild (<10%) dysplasia, blast cells <5% c
IDUS	No peripheral cytopenia a , MDS criteria not fulfilled, no MDS-related mutation b found, dysplasia in ≥10% of neutrophilic, erythroid, and/or megakaryocytes found, blast cells <5% c
CHIP	No peripheral cytopenia a , MDS criteria not fulfilled, one or more MDS-related mutations b found, no or only mild (<10%) dysplasia, blast cells <5% c