CODING CORNER: Time Your Lesion Excisions Right

Warning:  Length of incision doesn't equal excised diameter

When coding lesion excisions, the timing of your measurements is just as important as how you take them. 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, according to CPT guidelines.
Document Measurements Prior to Excision
Physicians 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 most 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.
Example: The physician 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 doctor allows a margin of at least 1.5 cm on all sides.
To calculate the excised diameter, you should begin with the lesion size (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 the excision diameter, be careful not to confuse the incision’s length with the excision size. Often, the physician 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, a dermatologist in Sherman Oaks, Calif.
Solution: Base your measurements on the lesion’s actual size before the physician performs the excision and prior to sending it to pathology, not according to the size of the surgical wound left behind.
Path Report Drives 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. CMS guidelines allow for this practice, which helps ensure claims’ accuracy.
 
Dx coding tip: Refer to the “table of neoplasms” in the Index to Disease portion of ICD-9 to locate an initial diagnosis for benign or malignant neoplasms. Always refer to the full definition in the Tabular List before settling [...]

- Published on 2005-10-11