A=Absolutely do it.There is high certainty that the net benefit is substantial.
B=Better to do it or benefits outway the risks. There is high certainty that the net benefit is moderate or there is moderate certainty that the net benefit is moderate to substantial.
C=Could use it. Offer or provide this service to individual patients based on professional judgment and patient preferences. There is at least moderate certainty that the net benefit is small.
D=Don’t use it! It’s contraindicated. USPSTF recommends against the service. There is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits.
I= Insufficient evidence to tell one way or the other. Th current evidence is insufficient to assess the balance of benefits and harms of the service.
Reference
https://www.uspreventiveservicestaskforce.org/Page/Name/grade-definitions