Unfortunately, AE-EHR does not facilitate locking down individual results like documents/notes. However, one approach a client has used is to add a "confidential" section to the patient chart and assign particular resultable items to that chart section. Permissions can then be set at the chart-section level to lock-down access.
In V11, login as TWAdmin and select Chart Admin -> Manage Sections. Add a "Confidential" section to the chart.
Next, associate chart items to the previously created chart section.
Lastly configure permissions for the chart section.
One caveat to consider is that this approach does not offer any "Break-Glass" functionality that documents/notes do.