Question: When I billed +17003 along with 99213-25, the 99213 only paid at half its allowable and the +17003 did not pay at all. The denial reason for the +17003 was, “N122 Add-on code cannot be billed by itself.” Is 99213 not acceptable code for +17003? Georgia Subscriber Answer: Your payer likely denied +17003 (Destruction (eg, laser surgery, electrosurgery, cryosurgery, chemosurgery, surgical curettement), premalignant lesions (eg, actinic keratoses); second through 14 lesions, each (List separately in addition to code for first lesion)) because you did not also report its designated base code, 17000 (Destruction (eg, laser surgery, electrosurgery, cryosurgery, chemosurgery, surgical curettement), premalignant lesions (eg, actinic keratoses); first lesion). When you look at the full descriptor for +17003, notice the parenthetical at the end that instructs to list +17003 separately in addition to the code for the first lesion. Code +17003 is used in addition to the code for the first such lesion destroyed, which is 17000. This instruction is reinforced by another parenthetical after code +17003 in CPT®, which tells you to use +17003 in conjunction with 17000. Note also that code +17003 is used for each lesion from two through 14. That means, if your clinician destroyed three premalignant lesions, you would report 17000 for the first one and +17003 two times (or with two units of service, depending on your payer’s preference); once for the second lesion and again for the third lesion. As for modifier 25 (Significant, separately identifiable evaluation and management service by the same physician or other qualified health care professional on the same day of the procedure or other service), if your clinician did a significant, separately identifiable E/M service in addition to the lesion destructions and the documentation supports that, then you may report the appropriate level of E/M service and append modifier 25, just as you did. The National Correct Coding Initiative includes an edit that bundles office/outpatient E/M codes (Column 2 or secondary) into 17000 (Column 1 or primary) in the absence of a modifier such as 25.