OASIS Alert

Must you always report a causative organism code?

When coding for an infected surgical wound in M1020/M1022, you’ll need to gather three types of information. First you’ll need to select a code that describes the infection itself. Next you must determine whether there is a known causative organism, and finally you need to know whether the patient has any antibiotic resistance. That means it could take as many as three codes to describe your patient’s surgical wound. Follow three steps and you’ll find the right codes every time.

Step 1: Code the infection. If you don’t have any more specific information about your patient’s infected surgical wound, 998.59 (Other postoperative infection) is your code.

Coding example: Your patient was admitted to home health following a coronary artery bypass graft (CABG) for wound care and teaching. The patient is receiving IV antibiotics at home due to post-op infection and cellulitis of the surgical wound on the chest. The patient has a diagnosis of coronary artery disease (CAD).

List the following codes for this patient, says Mary Deakle, HCS-D, COS-C, manager of compliance and education with Daymarck Home Healthcare Coding in Bismarck, N.D.

• M1020a: 998.59;
• M1022b: 682.2 (Other cellulitis and abscess, trunk);
• M1022c: 414.00 (Coronary atherosclerosis of unspecified type of vessel, native or graft);
• M1022d: V58.81 (Fitting and adjustment of vascular catheter); and
• M1022e: V58.62 (Long-term [current] use of antibiotics).

When coding for cellulitis, in most cases you’ll list the wound first, followed by the code for cellulitis. So in this scenario you’ll report the infected surgical wound code first followed by 682.2 for the cellulitis Deakle says.

Mistake: Some coders think that they must list a code to describe the causative organism for every infected wound they code. That’s not the case, Deakle says. In this scenario, the organism is not stated so there’s no need to code for the organism, she says.

Why? The "use additional code" note found at codes like 998.59 indicates that you should report a code for the causative organism, if known. If the causative organism isn’t known, as is often the case, there’s no need to add a code.

When you have more detailed information about the infected wound, be sure to take advantage of the more specific codes available. The codes in the 998 category are NEC, not elsewhere classifiable, so you should always use the more specific codes, if available, before defaulting to the 998 codes.

For example: 996.66 (Infection and inflammatory reaction due to internal prosthetic device, implant and graft; due to internal joint prosthesis) describes an infection of an internal joint prosthesis. And 997.62 (Amputation stump complication; Infection [chronic]), indicates a specific location and type of wound.

And when you do have information about the causative organism, your next step is to code for it.

Step 2: Code the causative organism. After the entry in your ICD-9 manual for some infection diagnosis codes, you’ll find a note prompting you to list an additional code to identify the organism that caused the infection. Remember, you should only list this additional code if you know the causative organism.

Look to the category 041.x (Bacterial infection in conditions classified elsewhere and of unspecified site) for causative organism codes related to infected wounds, says Lisa Selman-Holman, JD, BSN, RN, HCS-D, COS-C, HCS-O, consultant and principal of Selman-Holman & Associates and CoDR��"Coding Done Right in Denton, TX. You should always list the 041.x code as a secondary code, following the infection code, Selman-Holman instructs.

Coding example: Your patient was admitted to home health requiring dressing changes following drainage of a post-op abscess with MRSA following colon resection for a bowel obstruction. The patient is receiving IV antibiotics and the nurse will be flushing his catheter.

• M1020a: 998.59;
• M1022b: 041.12 (Methicillin resistant Staphylococcus aureus);
• M1022c: V58.81; and
• M1022e: V58.62.

There is no need to add a code for the abscess in this scenario because post-operative abscess is included under the infected surgical wound code, Deakle says. You know the causative organism in this scenario, so you can add a code for the MRSA (041.12).

While you’ll add V codes for fitting and adjusting the vascular catheter and for the antibiotics being provided, because the wound is complicated it’s not appropriate to list a V code for dressing changes, Deakle says.

Why? This isn’t the routine wound care indicated by V58.31 (Encounter for change or removal of surgical wound dressing). Coding for the infected wound indicates your agency is providing wound care along with observation of the wound and teaching about infection and other aspects of wound healing,

Step 3: Report resistance to antibiotics. While the 041.x (Bacterial infection in conditions classified elsewhere and of unspecified site) category codes now include information indicating the presence of MRSA in a Staphylococcus aureus infection, you’ll need to list an additional code to indicate other drug-resistant microorganisms.

When the causative organism is resistant to another type of antibiotics, even if it is Staph aureus, you’ll turn to the V09.x codes. For example, if the patient above had Staph aureus that was resistant to penicillin and Vancomycin, you would code for it as follows:

• M1020a: 998.59;
• M1022b: 041.12;
• M1022c: V09.81 (Infection with microorganisms resistant to other specified drugs; with resistance to multiple drugs);
• M1022e: V58.81; and
• M1022e: V58.62.

Note: Get more tips for accurate diagnosis coding from Eli’s Home Health ICD-9 Alert. Information on subscribing is online at www.elihealthcare.com or by phone at 1-800-874-9180.