Table 2.

Recommendation for Final Diagnosis Categories

Category	Definition	Examples	Comments
Not GVHD	No evidence for GVHD
Possible GVHD	Evidence of GVHD but other possible explanations	Obvious CMV enteritis with inclusions near the apoptotic changes Focal colonic ulcers with marked apoptotic cryptitis and destruction of crypts associated with use of MMF Co-infection with known active viral hepatitis Clinical features which suggest or favor a drug reaction	Indicate possible alternate diagnoses and reasons for suspicion
Likely GVHD	Clear evidence of GVHD without a competing cause of injury OR Clear evidence of GVHD with mitigating factors OR GVHD most likely diagnosis but relevant clinical information is limited OR GVHD is validated by sequential biopsy or by absence of competing diagnosis	Abundant epithelial apoptosis without clinical or histological evidence of drug injury or infection Evidence of CMV yet abundant apoptotic epithelial changes that are not associated with CMV infected cells by immunostaining Single or rare apoptotic epithelial changes without other features of active GVHD and no alternative explanations Limited sample or minimal or focal findings Proximity to recent chemotherapy or radiotherapy	Included old categories of “Consistent with” and “Unequivocal” GVHD