Internal Medicine Coding Alert

Remember 'Rule of Nines' When Calculating Patient's Burned Body Area

When a patient has multiple burns, make sure to include a dx for each one

When the internist treats a patient for burns, coders should make sure the treatment claim has at least two ICD-9 codes.

Why? The insurer expects to see, at a minimum, one diagnosis code to represent the burn's location, and another that specifies the percentage of the patient's body that was burned. Check out this three-step guide for choosing the right burn diagnosis codes on all of your claims.

Step 1: Choose Code for Burn Location

On nearly all of your burn treatment claims, you'll first need to select an ICD-9 code from the 940-947 set, says Debra Williams, CPC, coding supervisor at Horizon Billing Specialists in Grand Rapids, Mich. This ICD-9 code represents the anatomical location of the patient's burn, Williams says.

The 940-947 family is grouped by body area, and coders must remember to check for fourth- and fifth-digit requirements for these codes. All of the codes in this ICD-9 set require at least a fourth digit, and some, like 944.xx (Burn of wrist[s] and hand[s] ...), require a fifth digit. The fourth digits on these codes represent burn severity, and the fifth digits further specify body area.

Example: A patient with second-degree burns on his shoulder reports to the internist. On the claim, you should report 943.25 (Burn of upper limb, except wrist and hand; blisters, epidermal loss [second degree]; shoulder) to represent this burn.

Exception: If the patient's burn site is unspecified, you should not report a code from the 940-947 family. Instead, report 949.x (Burn, unspecified ...),  Williams says.

Step 2: Account for All Burn Sites

On burn claims, coders should also make sure that they have reported every burn on the patient's body. If the patient has multiple burns, you should include a diagnosis code for each one, Williams says.

For example, a patient has third-degree full-thickness skin burns to his right forearm and second-degree burns on his right thigh. On the claim, you would:

• report 943.31 (Burn of upper limb, except wrist and hand; full-thickness skin loss [third degree NOS]; forearm) for the forearm burn.
• report 945.26 (Burn of lower limb[s]; blisters, epidermal loss [second degree]; thigh [any part]) for the leg burn.

If the patient has burns of varying degrees in the same body area, the burn of higher severity takes coding precedence; report only the higher-degree burn on the claim, Williams says.

For example, a patient has second-degree burns on her back and first-degree burns on her abdominal wall. In this scenario, you would report 942.24 (Burn of trunk; blisters, epidermal loss [second degree]; back [any part]).

Step 3: Use 'Rule of Nines' to Select 948.xx Code

After selecting the proper code(s) from the 940-947 code group for your burn patient, you're ready to choose a code from the 948.xx (Burns classified according to extent of body surface involved) code set, which you'll also want to include on your burn treatment claim.

All 948.xx diagnosis codes require a fourth and fifth digit; the fourth digits represents total body surface area (TBSA) burned, and the fifth digit represents the percentage of third-degree burns on the patient.

To select the appropriate fourth digit, you'll need to use the "Rule of Nines," says Todd Thomas, of Thomas & Associates in Oklahoma City. The "Rule of Nines" is a breakdown of the patient's TBSA.

These are the TBSA breakdowns, Thomas says:

• Head and neck (collectively), right arm, and left arm each equal 9 percent of TBSA. So if the patient's right arm was burned, the Rule of Nines states that TBSA burned is 9 percent.

• Back trunk, front trunk, left leg, and right leg each account for 18 percent of TBSA. (You can divide the front and back trunk into upper and lower portions equaling 9 percent each. You can also divide each leg into front and back, with each segment equaling 9 percent).

• Genitalia equal 1 percent of TBSA.Consider this example: A patient who put out a grease fire in his kitchen suffered first-degree burns to his entire head and neck and second-degree burns to his entire left arm. In this scenario, the head and neck burns constitute 9 percent TBSA, and the burn to the left arm represents 9 percent TBSA; this equals 18 percent TBSA. The appropriate 948.xx code (carried out only to the fourth digit) is 948.1x (... 10-19 percent of body surface)

Note: To choose the most accurate 948.xx code, you must also know the TBSA of the patient's third-degree burn areas. This is because the fifth digit of the 948.xx represents the percentage of third-degree burns the patient has, Williams says.

Suppose the patient in the above example had first- and second-degree burns to 19 percent of TBSA, with no mention of third-degree burns. Based on the information in the example, you should report 948.10 (... burn [any degree] involving 10-19 percent of body surface; less than 10 percent or unspecified).
 
Also: The above Rule of Nines explanation does not apply to children with burns. For children, the Rule of Nines breaks down thusly, Thomas says:

• Head equals18 percent of TBSA.
• Chest and abdomen equal 18 percent of TBSA.
• Back equals 18 percent of TBSA
• Right and left arm each equal 9 percent of TBSA.
• Right and left leg each equal 14 percent of TBSA.

Other Articles in this issue of

Internal Medicine Coding Alert

View All