Have you joined the website NPPC ACEs? They have links to most of the relevant research there.
I think your question shows a bit of a difference in thinking from those who are using ACEs screening. It is not as simple as an ACE of 4 needing a referral. That would be simple. It is possible that a person with an ACE of 6 has a good relationship with a caregiver, feels safe most of the time, has good school and church support, and no current medical or mental health issues. They don't currently need a referral but its good to keep the number in mind if future medical or mental health issues come up. It is also possible for a person with an ACE of 2 to have had loss of a primary caregiver, minimal school support, no buffering or mental health support and is having an increase in headaches and asthma. That person would warrant a referral. The ACEsaware.org website has a nice algorithm chart for use but I don't know that there is prospective research behind it. It is really incumbent on the doctor using the screening tool to be comfortable talking about not only ACEs and health outcomes but how caregivers and communities can also support resilience and protective and compensatory experiences. Parenting classes are also one of the most requested interventions and are not a medical intervention.