Part B Insider (Multispecialty) Coding Alert

Question: Some of our payers deny claims with modifier 33 because they state the modifier is invalid. Can you explain this modifier to me and how we should be using it?

Answer: Modifier 33 (Preventive services) was a late addition to CPT® 2012; you'll find it in the Appendix A but not inside the front cover with other common modifiers. The full descriptor reads as follows:

When the primary purpose of the service is the delivery of an evidence based service in accordance with a US Preventive Services Task Force A or B rating in effect and other preventive services identified in prevent services mandates (legislative or regulatory), the service may be identified by adding 33 to the procedure. For separately reported services specifically identified as preventive, the modifier should not be used.

Modifier 33 isn't appropriate for every preventive service. Only report it for services that 1) are not inherently preventive and 2) were provided as preventive in the particular situation.

Example: Colonoscopy as a means of screening for colorectal cancer carries a US Preventive Services Task Force rating of 'A' under appropriate circumstances. However, there is no CPT® code that specifies a colonoscopy done on a preventive basis. Thus, in this situation, a practice could denote a screening, or preventive colonoscopy, by appending modifier 33 to code 45378 (Colonoscopy, flexible, proximal to splenic flexure; diagnostic, with or without collection of specimen(s) by brushing or washing, with or without colon decompression (separate procedure)). An appropriate diagnosis code (e.g. V76.51 (Special screening for malignant neoplasms; intestine; colon)) can also help identify the service as preventive rather than diagnostic or therapeutic.

Modifier 33 was created in response to the Patient Protection and Affordable Care Act, which requires most health plans to cover certain preventive services without patient cost sharing. The modifier helps physicians indicate such services on their claims.

As noted, you should not append modifier 33 to any code that is already identified as preventive in CPT®. For instance, you shouldn't append modifier 33 to codes such as 99397 (Periodic comprehensive preventive medicine reevaluation and management of an individual including an age and gender appropriate history, examination, counseling/anticipatory guidance/risk factor reduction interventions, and the ordering of laboratory/diagnostic procedures, established patient; 65 years and older) or G0101 (Cervical or vaginal cancer screening; pelvic and clinical breast examination).

Tip: Medicare doesn't recognize modifier 33. Private payers may or may not accept modifier 33, so apply it on an individual basis.