Coding and Billing

Coding Rules for Special Diagnostic Testing

Kevin Soong, OD, performs diagnostic testing using an OCT in the office of ROB Professional Editor Laurie Sorrenson, OD, FAAO

Kevin Soong, OD, performs diagnostic testing using an OCT in the office of ROB Professional Editor Laurie Sorrenson, OD, FAAO

Coding rules to maximize reimbursement when doing special diagnostic testing.

By Mark K. Davis, OD

Sept. 6, 2023

Having traveled over much of Texas to fill in for optometrists, I have had the opportunity to see the diagnostic equipment that is most common in optometric offices. I am also able to see who the “early adopters” are of the latest pieces of equipment. I don’t believe I have been to any office that doesn’t have at least one piece of special diagnostic equipment. So, let’s dive into special diagnostic testing.


Each diagnostic test has two components:

Technical component (TC modifier) – if your practice just performs the test and sends the results back to the requesting provider for interpretation. There is a percent of the allowable charge.

Examples of the breakdowns of the percentage of the two components on a few common diagnostic tests:


Each of the diagnostic tests must have (1) a written order in the chart for the special testing, with medical rationale and (2) a separate interpretation and report (there are some exceptions, such as gonioscopy). Refer to the CPT manual for the requirements on each special diagnostic test. It will state in the definition of the test “with interpretation and report,” if one is needed.

An example of a written order could be:

“Order glaucoma evaluation to include OCT, VF, pachymetry, photos and gonioscopy due to several risk factors for POAG”

All the tests need not be performed on the same day, as some cannot be, based on the NCCI edits, covered in a previous article on modifiers. The most common and well known is that you cannot bill for fundus/disc photos (92250) and OCT (92133) on the same day. Again, there are always exceptions. In this case, using the 59 modifier would override the NCCI edit.

Interpretation and Report

So, what is included in the Interpretation & Report?  At a minimum the following:

Patient name and date of service

Type of service: visual field or fundus/disc photos or OCT, etc.

Reliability of test: good quality or

technical difficulty, but still adequate or

repeat test required

Findings and Implications: within normal limits or

outside expected limits or


Comparative Data: base line exam or

follow-up exam – essentially stable or progression of defect

Management:  medication change or

recommend surgery or

further diagnostic testing recommended or


Physician signature & date

For information on CMS guidelines for Interpretation and Report:

An Interpretation and Report must be generated for EACH diagnostic test performed. You cannot just scribble your thoughts on the printout from the diagnostic test, to pass an audit. I have seen this many times.

New Diagnostic Test Codes

Two new diagnostic testing codes were added in 2020:


Extended ophthalmoscopy of peripheral retina

With retinal drawings

With scleral depression


Extended ophthalmoscopy of optic nerve & macula

With drawings

No scleral depression

These codes replace codes 92225 and 92226.  Also, you cannot bill fundus photos (92250) on the same day as these diagnostic tests.

Many of the EHRs I have used at various offices have tabs and check boxes for Special Diagnostic Testing. Some even remind you to complete the report! This makes reporting exceptionally easy.

Unlisted Ophthalmological Code

What about a diagnostic ophthalmological procedure that does not have a specific CPT code?  Then use CPT code 92499. You must put a description in block 19 and most often you will be denied and have to go through the appeals process. Is it worth your time?  One last note, modifiers are not appended to unlisted codes. I racked my brain and the only code I could think of without a CPT I code, which was not included in a comprehensive ophthalmological exam and that did not have a CPT III code, was Contrast Sensitivity. I’m sure there may be others.

Category  III Codes (Temporary Codes)

Category III codes exist so data can be collected on emerging technologies, services and procedures. This data is then used to determine whether new Category I codes are needed. The codes end in the letter “t.” No relative value units (RVUs) are assigned to them on a national level, and without a payer policy there is no payment coverage. You should have Medicare patients sign an Advance Beneficiary Notice (ABN). There will be more information on ABNs in a future article.

Until next time…”Happy Coding.”

Mark K. Davis, OD, is a Therapeutic Optometrist and Optometric Glaucoma Specialist, Diplomate, American Board of Optometry, Adjunct Assistant Professor, University of Houston College of Optometry and Chief of Optometry, 147th Medical Group. He is Lt Col, Texas Air National Guard, Ellington Field JRB, Houston, Texas.

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