Since this is a non-covered service by Medicare and several payers, it is difficult to find guidance or any official guidelines on acupuncture. The following two articles are frequently cited and provide helpful information; however, they are not official guidance and do not directly answer your question:
Mu understanding is that the "rules of 8" apply only to physical therapy services, though some payers include occupational and speech language pathology as well. The closest "authoritative" guideline I can find is a PowerPoint presentation from the American Association of Oriental Medicine (AAOM) in 2005 (so over 10 years old). (
http://www.aaom.info/cptcodes.pdf)
Slide 28 states:
More about the “15 minute” time intervals.
• Pre and post service time is estimated to be minimally 6 minutes. If you then spend approximately 10 minutes with locating points, putting in the needles, removing needles, etc., then that would total about 16 minutes.
• Important - 15 minutes means 1 to 15 minutes.
• The first code (97810 or 97813) means Less Than 15 minutes.
• 16 minutes means that you would bill the initial 15 minutes (97810 or 97813) and the next 15 minutes (97811 or 97814).
From an auditing perspective, if pre- and post- service work is included and expected to be at least 6 minutes, in addition to the actual service, then I think you would be hard pressed to justify billing acupuncture codes if total time is less than 8 minutes. Furthermore, unless stated otherwise (as with CPT 96570 and 96571 which give specific instructions for using modifier 52 if the full service time of 30 minutes and 15 minutes are not met), a majority of the timed CPT codes in the Medicine section require that the services be performed for at least half of the time stated (16 minutes or more for a timed code of 30 minutes; 31 minutes or more for a timed code of 1 hour). Therefore, while not explicitly stated, it can certainly be inferred from the intent of the code (pre-, intra-, and post- service time expectations) along with the precedence set forth in other sections of CPT that the "8 minute rule" applies for determining when you can bill a full unit, at least for the initial 15 minutes of service.
As always, check your payer policies as they may have differing guidelines.
Hope this helps!