Medicare has approved acupuncture for low back pain but services must be provided in a primary care practice and submitted under an MD's license. At this time, an acupuncturist cannot submit claims directly to medicare. This is because acupuncturist are not approved to be medicare providers yet.
Secondary Medicare plans are different. An acupuncturist can submit insurance claims to secondary medicare plans. Secondary plans will cover what Medicare wont cover. Premera and Regence etc are examples of this, but make sure that your card says 'Secondary.'
Supplemental insurance plans do not cover acupuncture. Supplemental plans will only cover services that Medicare covers. Supplemental plans pay the remainder of the claim after Medicare pays for their portion. If Medicare doesn't cover a service, supplemental insurance will also not cover the service. AARP is an example of this. Your card will say 'Supplemental.' Some Regence and Premera plans have supplemental coverage instead of secondary coverage so make sure to check your card.
If you have an additional Medicare insurance plan, take a look at your card and see if it says Secondary or Supplemental. If it says Secondary then call your insurance plan and ask if you have acupuncture benefits.