Many physician practices are denied by third party payers when billing for a visual acuity test with a well child visit. The code for visual acuity testing is 99173.  See the CPT® book for a complete definition of this code.  This is a screening test of visual acuity, quantitative, bilateral, such as a Snellen test.  The nurse or medical assistant asks the patient to read the eye chart from down the hall.

The code is not bundled into preventive medicine services, and should be separately paid. 

In 2009, the AMA added language into its editorial comments in the CPT® book.  Take a moment to review that language which says, "Other identifiable services unrelated to this screening test provided at the same time may be reported separately [eg, preventive medicine services].

Some payers may require a 25 modifier on the E/M service when submitting the claim.

With the addition of this language, which is an absolute statement that the visual acuity screening should be paid separately and not considered incidental or bundled into the preventive medicine service, practices should collect this money.  It may require a re-negotiation at contracting time with third party payers.

Medicare assigns it a non-covered status.  This means you could bill the patient for the service.

The service is not a high dollar item.  However, for Pediatricians and Family Physicians who do a lot of well child visits, the volume is significant. 

The AMA also has a initiative to help physicians identify and respond to payers who improperly bundle services.