Dermatology Coding Alert

Infants require different figures

To assign the required fourth and fifth digits for diagnosis category 948.xx, you must apply the "rule of nines" set forth in ICD-9.
 
The rule of nines divides the body into nine general areas and assigns a percentage value to each:
 
• The head and neck, the right arm, and the left arm each equal 9 percent.

• The back trunk, front trunk, left leg and right leg each equal 18 percent (the front and back trunk are divided into upper and lower segments, and each leg is divided into back and front segments, each equaling 9 percent).
 
• The genitalia equal 1 percent.

Exception: The above percentages are slightly different for babies, due to the relatively large size of their heads (18 percent). Although back and front remain at 18 percent and arms remain at 9 percent, the guidelines trim the legs to

14 percent each to account for the increased size of the head and face.

Use Rule to Describe Extensive Burns

When to use it: You only need to use the rule of nines "when burns are extensive over a body area," says Linda Martien, CPC, CPC-H, coding consultant with National Healthcare Review Inc. in Woodland Hills, Calif.
 
Example: If a patient has a small first-degree burn on her forearm, you would simply report 943.11 (Burn of upper limb, except wrist and hand; erythema [first degree]; forearm), Martien says.
 
If a patient has extensive burns covering her upper and lower back, however, the rule of nines tells you that each back segment is worth 9 percent. Therefore, the total body area burned equals 18 percent -- meaning you would report 948.1x to indicate that the patient has burns on 10-19 percent of her body.
 
Important: You should claim the total percentage assigned to a specific body area even if the entire area does not have burns. For example, if only a portion of the front right leg is burned, you should claim the full 9 percent for that area.