severity of adverse event AE severity G0 YH, SS a severity of AE that shows sign and symptom within normal limits. AE severity Grade 0 CTCAE4: E10004 (Grade 0 Adverse Event) Note the AE severity Grade 0 equals to CTCAE G0 AE severity. Web: http://ncicb.nci.nih.gov/xml/owl/EVS/ctcae.owl#Grade_0_Adverse_Event