Diagnostic testing services are a crucial component of the diagnostic and medical decision-making processes. Testing options are constantly evolving, and their contribution to patient care is essential. Because coverage varies by payer, frustration can often occur with regard to insurance coverage variations in documentation requirements, performance limits, and bundling edits.

The following tips and checklists are designed to curb that frustration.


Medicare Administrative Carriers (MACs) publish Local Coverage Determinations (LCDs) and National Coverage Determinations (NCDs) for certain medical services. When the LCDs for retina diagnostic testing services are published, they provide guidance in areas such as these:

  • Indications;
  • Medical necessity;
  • Limitations and frequency edits;
  • Documentation requirements;
  • Approved CPT and ICD-10 codes.

LCDs may vary by region, and they are revised periodically. To review and maintain a current copy of the LCDs published by your MAC, visit aao.org/lcds.

Commercial and Medicaid carriers may also have policies related to diagnostic testing services. Some payers may have these policies available on their website or portal.

Important tip: Do not assume you can apply one payer’s rule or perceived rule to all payers.

Due to the variations in payer policies, the first step in billing for testing services is to find out who the payer is and check whether that payer has a published policy. Next, identify the unique requirements. For Medicare Part B, reviewing the active LCD is essential and will provide direction.

For a retina specialist practicing in Kentucky or Ohio, for example, the MAC, Cigna Government Services (CGS), has an active LCD for fluorescein angiography (LCD L34175), effective October 1, 2016. This policy provides guidance for ordering fluorescein angiography (FA):

  • Frequency: “Fluorescein angiography is considered medically necessary no more than nine (9) times per eye in 365 days. Claims exceeding this frequency will be suspended and reviewed for medical necessity.”
  • Medical necessity: “Fluorescein angiography with interpretation is medically necessary as an adjunct to the diagnosis of chorioretinal vascular abnormalities especially relating to choroid neovascularization, noninfective vasculitis, and age-related macular degeneration. It may also be appropriate in evaluating intraocular tumors, visual loss in systemic disease, acute exudative inflammations such as toxoplasmosis and optic disc edema.
    “Medical necessity for such angiography would generally be in the context of a changing clinical picture. FA may be useful in diabetic retinopathy in identifying ischemia and neovascularization, locating microaneurysms, and defining macular edema.
    “FA following treatment, for example, of choroidal neovascularization (CNV) is necessary to monitor for recurrence or to detect additional treatable disease. Usually this is performed on the basis of a change in the clinical picture similar to the way it is employed prior to treatment. However, FA may be performed following treatment without clinical change in order to detect occult lesions. This will occur most often in CNV and very rarely in other diseases.”
  • Screening: “Studies performed for screening will be denied by Medicare as not medically necessary.”

The policy also contains additional information, such as identifying CPT codes and ICD-10 codes that support and do not support medical necessity, and documentation that supports medical necessity.


Insurance policies often provide documentation requirements. From these policies, an internal checklist can be created as a resource. The checklist on the following page provides guidance for the documentation requirements for FA. Note, however, that it represents typical requirements and should be revised per individual payer policy.



Frequently, it is necessary to perform multiple diagnostic testing services on the same day. When this occurs, it can be a challenge to determine the correct coding.

Medicare publishes quarterly National Correct Coding Initiative (NCCI) edits to identify CPT codes that are considered bundled, and therefore not separately payable, when performed on the same day. Link to these edits can be found at aao.org/coding and in the AAO’s Complete Guide to Retina Coding.

There are two types of bundled codes: mutually exclusive and comprehensive.

  • Mutually exclusive codes can never be unbundled and have an indicator of “0”.
  • Comprehensive codes with an indicator of “1” may be paid separately under limited circumstances and must meet the definition of modifier -59 or per specific LCDs.

Table 1 shows an example of NCCI edits for 92133 optic nerve OCT, 92134 posterior segment OCT, and 92134 posterior segment OCT and fundus photography (FP).

Table 2 is a quick reference guide for some of the common diagnostic testing services performed in a retina practice. This resource can be expanded to include other tests or services to allow coders to identify NCCI edits promptly.