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Modifier Coding Alert

Ob-Gyn Spotlight:

Grab Modifier GG for Mammogram Screening and Diagnostic in Same Day

Pay attention to patient age and sex for mammography screenings.

Your physician may sometimes order and interpret mammogram films before the patient leaves the building. Determining the correct coding for these same-day procedures can throw a wrench in your day. 

Continue reading to learn more about that and to learn what you need to know to curb claim denials.

Report a Screening and Diagnostic

Your physician may perform a screening as well as a diagnostic mammogram on the same day, for example, when a patient presents for a screening mammogram, and your radiologist detects a suspicious abnormality on one breast. This may necessitate a separate ultrasound exam on the same date. 

In this case, you should report both services using G0202 (Screening mammography, producing direct digital image, bilateral, all views) and G0204 (Diagnostic mammography, producing direct digital image, bilateral, all views) or G0206 (… unilateral, all views). Then, attach modifier GG (Performance and payment of a screening mammogram and diagnostic mammogram on the same patient, same day) to the diagnostic ultrasound code. 

“The GG modifier is necessary for the second diagnostic mammogram because G0202 and G0204/G0206 are not typically billable on the same date of service,” says Brad Hart, MBA, MS, CMPE, CPC, COBGC, president of Reproductive Medicine Administrative Consulting in West Orange, N.J. “The GG modifier is not necessary or appropriate if the diagnostic mammogram happened on a calendar day other than the day the screening mammogram occurred.”

Note: Your physician may order more films if the screening reveals a potential problem. CMS also allows the radiologist to order additional films. According to CMS, “The radiologist who interprets screening mammography may order and interpret additional diagnostic films while the beneficiary is still at the facility.” Meaning Medicare will pay for both the screening and diagnostic exams with the use of modifier GG.

CMS states in Change Request 2632 ( that “Performance and payment of a screening mammography and diagnostic mammography on same patient same day is billed with the diagnostic mammography code to show the test changed from a screening test to a diagnostic test. Contractors will pay both the screening and diagnostic mammography tests. Modifier GG is for tracking purposes only.”

Submit Modifier GH on Diagnostic Mammogram Only 

When your payer approves of modifier GH (Diagnostic mammogram converted from screening mammogram on same day), you’ll use it as a reporting mechanism to indicate that the diagnostic mammogram was converted from a screening on the same day of service. CMS established this modifier mainly for the purpose of collecting data on the number of diagnostic mammograms performed on Medicare patients as a result of screenings on the same day. 

Medicare states you can only use modifier GH for claims with dates of service from October 1, 1998 through December 31, 2001. Therefore you shouldn’t use GH with claims dated January 1, 2002 and beyond. Some payers do allow the use of modifier GH and you should contact your payers to learn their policy.

According to Palmetto GBA, you may submit modifier GH with CPT® codes 77055 (Mammography; unilateral), 77056 (Mammography; bilateral), HCPCS codes G0204 (Diagnostic mammography, producing direct digital image, bilateral, all views), and G0206 (Diagnostic mammography, producing direct digital image, unilateral, all views). Palmetto’s policy can be seen on the following site:

Example: A patient comes in for a bilateral screening mammogram. Later the same day an abnormality is found and it is determined that this exam should be considered diagnostic. You would code the mammogram as 77056 (Mammography; bilateral) with a GH attached.