Modifier AT (active treatment) defines the difference between active treatment and maintenance treatment.

The AT modifier is required under Medicare billing to receive reimbursement for CPT codes 98940-98942. For Medicare purposes, the AT modifier is used only when chiropractors bill for active or corrective treatment (acute and chronic care).

Every chiropractic claim for 98940, 98941 and 98942, should include the AT modifier if active or corrective treatment is being performed. Claims that do not contain modifier AT will deny.

When your office receives a request for medical records to substantiate the chiropractic services you rendered and billed to Medicare, our nurse reviewers review the documentation and verify that all the required documentation has been met. If you met the documentation requirements, the nurse reviewers will send the documentation to a chiropractic consultant to determine the medical necessity of the services. If you did not meet the documentation requirements, the nurse reviewers will deny the services based on the lack of documentation.

Yes, if you submit the initial examination findings with each billed subsequent visit when responding to medical documentation requested by us or the Comprehensive Error Rate Testing (CERT) program, it is acceptable.

X-rays must be reasonably proximate to the initiation of a course of treatment. Unless more specific X-ray evidence is warranted, an X-ray is considered reasonably proximate if it was taken no more than 12 months prior to or 3 months following the initiation of a course of chiropractic treatment. 

In certain cases of chronic subluxation (e.g., scoliosis), an older X-ray may be accepted provided the beneficiary's record indicates the condition existed longer than 12 months and there is a reasonable basis for concluding that the condition is permanent.