Medical necessity and frequency are keys to billing for diagnostic tests.


Winston Churchill once said that Russia was “a riddle wrapped in a mystery inside an enigma.” The same might be said of the guidelines for the frequency of performing diagnostic tests in patients with age-related macular degeneration (AMD). Extended ophthalmoscopy, retinal photography, optical coherence tomography (OCT), or even newer tests which have no specific CPT (Current Procedure Terminology) code each have their own rules for reimbursement.

It all depends on medical necessity. The test must investigate any medically sound reasons suspected for further vision loss—not for your documentation or the patient’s education. For example, a patient with dry AMD suspected of converting to wet AMD would constitute medical necessity.

With Medicare, each state sets its own local coverage determinations (LCDs). As I noted in “Navigating the New Codes for OCT” article in the February issue of Ophthalmic Office, some states have specific LCDs for OCT frequency. For states that don’t, the guideline becomes professional judgment and medical necessity. Only a few states have LCDs for retinal photography. And Medicare discourages billing for OCT and retinal photography in the same day.

The non-Medicare plans have few policies to guide us in the frequency of diagnostic tests for AMD, leaving us, again, to professional judgment and medical necessity.

However, non-Medicare plans do use a “black box edit”—an unpublished frequency limit known only to those within the insurance company. Any claim beyond that secret number triggers a review. In many cases, you won’t know until you submit the bill and the plan questions it.

• Macular pigment optical testing (MPOD) is a newer test for AMD, but no CPT code exists for it. Either submit the claim with 92499 code (for unlisted procedure) with documentation of medical necessity or simply bill the patient. The latter is the most straightforward. Doctors I’ve talked to are basing fees on their costs.

• Extended ophthalmoscopy (codes 92225 and 92226) is a test that gets many questions. If you do it and see no macular changes, you can’t bill for it. Usually with AMD, though, we know the patient has undergone some change before we perform it. I’m not aware of any frequency limits on extended ophthalmoscopy.

• Genetic testing for AMD is emerging thanks to recent commercial tests, but it can’t be billed through laboratory CPT codes. The only payment available is from regular office call codes.

• If you have OCT that uses autofluorescence, this procedure is not fluorescein angiography in its classic sense—that is, via injection. Avoid the 92235 code (for fluorescein angiography, passive). This topic is still evolving.

Because AMD carries risk for vision loss, the office level for billing Medicare can be either 3, 4, or 5. Many optometrists are hesitant to bill level 5, but in a case of severe AMD with true vision loss and a real threat of more vision loss, especially if complicated with another disease such as glaucoma, a level 5 is justifiable. In fact, Medicare factors that 1% to 2% of a typical doctor’s billings will be at this level.

Alan Homestead is an optometric physician practicing in Seattle and a consultant on coding issues and practice management.



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