Facet joint pain or si joint pain? pain is located in lower left, 2 inches from spine (l5-s1 area). no reffered pain. 2 somewhat positive facet blocks

Hard to say: It seems simple, but that is sometimes difficult to tell, partly because both structures can cause pain in that area. If an injection in the si joint relieves 100 percent of the pain, then that is considered diagnostic for si pain and rf is usually the next step. If facet injection had relieved all your pain, then it is considered facet based, some patients may have multiple sources of pain.

Can Be both: However if the facet block gave you 70-100% pain relief, then more likely to be your fact joint. If less than 50% relief, then consider the SI joint as a definite source of your pain. Also if not ruled out already, I often find things like spinal stenosis or herniated discs also have this same pattern of pain.