Internal Medicine Coding Alert

Question: Recently Medicare denied my claim for 94799, which I used when my internist performed maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) tests. Which code(s) should I have used?

Minnesota Subscriber

Answer: CPT offers no codes that describe maximum inspiratory pressure and maximum expiratory pressure. Some internists simply do not charge for these services, although others attempt payment with 94799 (Unlisted pulmonary service or procedure). But as you know, insurers often deny this code, because unlisted-procedure codes carry no descriptions, fees or work values. 
 
Before reporting 94799, you should know that both Medicare and private carriers will deny the claim pending review of your physician's documentation that supports the provided service. And insurers require that you send the physician's documentation and his or her charge for the service with the claim. You may also help your chances if you supply the carrier a rationale for the chosen fee, which should be comparable to a procedure with the same amount of work and effort. 
 
For example, you may compare MIP with spirometry (94010, Spirometry, including graphic record, total and timed vital capacity, expiratory flow rate measurement[s], with or without maximal voluntary ventilation). Include a cover letter with the claim that references the other procedures and highlights the similarities.
 
In some cases, insurers may not pay for 94799 even if you support the code with proper documentation. For instance, if your physician performs an experimental procedure, you can almost guarantee that the payer will deny your claim.