What is the ICD‑10‑CM code for a routine screening mammogram in an asymptomatic patient?

ICD-10-CM Code for Routine Screening Mammogram

Use ICD-10-CM code Z12.31 for routine screening mammography in asymptomatic average-risk women. 1

Code Specification and Application

• Z12.31 is the designated code for encounters specifically for screening mammography in women without symptoms or known breast abnormalities 1
• This code applies to all asymptomatic average-risk women undergoing routine screening, regardless of age (starting at 40 years) or breast density 1
• The code remains Z12.31 for both annual and biennial screening intervals, as recommended by the American College of Radiology 1

Critical Coding Distinctions

Do not use Z12.31 for diagnostic mammography. 2 The following scenarios require different coding:

• Symptomatic patients (breast pain, palpable mass, nipple discharge) require diagnostic codes based on the specific symptom 2
• Follow-up of abnormal findings from prior imaging requires diagnostic coding, not screening codes 2
• Surveillance after breast cancer treatment may use diagnostic mammography codes even in asymptomatic patients, depending on institutional protocol 2
• Patients with prior breast-conserving therapy may be coded as diagnostic examinations even when asymptomatic, though some institutions return them to screening protocols 2

Age-Appropriate Screening Context

While Z12.31 is the code for all screening mammograms, the American College of Radiology provides these screening recommendations:

• Ages 40-44: Opportunity to begin annual screening with Z12.31 1
• Ages 45-54: Annual screening strongly recommended, coded as Z12.31 1
• Ages 50-69: Biennial screening acceptable, though annual provides greater mortality reduction (40% vs 23%), both coded as Z12.31 1
• Age 70+: Continue screening with Z12.31 if life expectancy exceeds 10 years 1

Common Coding Pitfalls to Avoid

• Never use Z12.31 for women with breast symptoms, even if they are due for routine screening—the presence of symptoms mandates diagnostic coding 2
• Do not confuse screening with diagnostic tomosynthesis—screening digital breast tomosynthesis also uses Z12.31, while diagnostic tomosynthesis requires different codes 2
• Avoid using Z12.31 for high-risk surveillance in women with genetic mutations or strong family history who may require supplemental MRI—though mammography remains part of their screening, additional risk-based codes may apply 3