Warning: Length of incision doesn't equal excised diameter
When coding lesion excisions, when you take measurements is just as important as how you take them.
According to CPT, to determine the appropriate lesion excision code, you must measure the lesion's diameter at its widest point and add to that measurement double the width of the narrowest margin.
Document Measurements Prior to Excision
Surgeons should calculate and document the size of the lesion excision before removing the lesion and sending it to pathology for analysis. This is because the lesion's size will be smaller as soon as the first incision releases some of the tension on the skin, and the sample will likely shrink further when placed in formaldehyde. And, because codes for excision of benign (11400-11471) and malignant (11600-11646) lesions are "size-based," a shrunken sample will mean smaller reimbursement, too.
"Taking measurements at the appropriate time is a matter of both clinical and coding accuracy," says Michelle Logsdon, CPC, CCS-P, of Falcon Practice Management LLC, in Bayville, N.J.
Example: The surgeon excises an irregularly shaped, malignant (as later determined by a pathology report: see below) lesion from just below the patient's right shoulder. The lesion measures 2 cm at its widest. To ensure removal of all malignancy, the surgeon allows a margin of at least 1.5 cm on all sides.
To calculate the excised diameter, you should begin with the size of the lesion (2 cm) and add the width of the narrowest margin multiplied by 2 (1.5 x 2, or 3 cm total) for a total of 5 cm (2 + 3 = 5). In this case, therefore, you should report 11606 (Excision, malignant lesion including margins, trunk, arms or legs; excised diameter over 4.0 cm).
Possible problem: When calculating excision diameter, be careful not to confuse the length of the incision with the size of the excision. Often, the surgeon will make an incision that is longer than the lesion because "the longer you make that ellipse, the flatter your scar is going to be," but this has no bearing on code selection, says Allan Wirtzer, MD.
Solution: Base your measurements on the actual size of the lesion before the surgeon performs the excision and prior to sending it to pathology, not according to the size of the surgical wound left behind.
Wait for Path Report Before Choosing Diagnosis
Because CPT classifies lesions as either "benign" or "malignant," you should always wait for the pathology report before selecting ICD-9 or CPT Codes to describe the types of lesions and excisions. [...]