billing & coding
Coding Average Office Visits
Establish guidelines for your practice.
CARLA MACK, O.D.

Accurate coding and billing can resemble a bowl of alphabet soup. Following are common guidelines to help put you on the right track in determining correct diagnosis codes.

Proper coding

Procedure codes and diagnosis codes go hand in hand to numerically describe a patient visit and clinical outcome. Diagnosis codes or International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes help describe the presenting clinical picture and justify medical necessity for procedures. When verifying a patient condition or symptom in the ICD-9-CM book, refer to the alphabetic listing first and verify the code in the tabular or numeric listing. Always code as specifically as possible, avoiding XXX.9 codes or codes listed as unspecified.

Back to basics

One of the most basic, but often forgotten, rules of coding is that the primary diagnosis should always represent the patient's chief complaint or chief presenting symptom. Consider the patient who presents with distance vision complaints, which you determine to be caused by myopia. This patient also presents with increased intraocular pressures, asymmetric cup-to-disc ratios, and a family history of glaucoma. Your coding should be as follows: primary diagnosis code of 367.1 for myopia; secondary diagnosis code of 365.01, glaucoma suspect with open angle and borderline findings. If this same patient presents and requests a glaucoma evaluation with the same ocular findings, the primary diagnosis code would be 365.01, glaucoma suspect, to correspond to the chief complaint.

When the exam outcome is uncertain, probable, suspected, questionable or rule-out, and there is no existing code, code the patient's presenting signs or symptoms. In the case of both a confirmed diagnosis and corresponding presenting symptoms, it's not necessary to code for both, unless the presenting symptoms are not fully explained by the diagnosis code.

Report coexisting conditions when both require or affect the treatment. Consider a patient presenting with a peripheral corneal ulcer and secondary anterior chamber inflammation. Coding should include primary and secondary diagnosis codes of 370.01 for marginal corneal ulcer, and 364.04 for secondary anterior uveitis. Code chronic diseases for the duration of treatment.

What's new?

If you're just getting the hang of ICD-9-CM codes, HHS is expected to release an ICD-10 conversion in the near future. It will not only add 5,500 new codes, but will change the entire coding reference system to one that is alphanumeric rather than simply numeric.

DR. MACK IS DIRECTOR OF CLINICS AT THE OHIO STATE UNIVERSITY COLLEGE OF OPTOMETRY. SEND E-MAIL TO CMACK@OPTOMETRY.OSU.EDU.