CCS Prep

Always a Challenge: Complication Coding

Take the "complicated" out of complication coding.

Among coding topics, none elicits more discussion among coding, clinical and compliance professionals than complication coding. It's considered one of the more challenging aspects of coding, but both novice and seasoned coders should understand not only the nuts-and-bolts of complication coding, but also the implications of assigning these codes haphazardly.

Generally, a complication is defined as "a condition arising during the health care episode that modifies the course of the patient's illness or the medical care required." But for coding purposes, this definition is not sufficient in helping determine whether or not an event is a "codable" complication. The terminology "postoperative complication" may be misleading in itself, because it may refer to somewhat common clinical events that occur after the time of surgery. Not all conditions that may occur after a surgical procedure should be always classified as complications. The following subcategories of "complications" may be helpful in differentiating various types of post-procedural events:

 Misadventure: an adverse event that occurs during medical or surgical care and is caused by that treatment. Example: intra-operative accidental laceration.

 Early complication: a condition that generally occurs within 29 days after the procedure and isn't evident at the time of the surgical procedure. Example: wound dehiscence or wound infection.

 Late complication: a condition that occurs or persists > 29 days after the procedure. Example: post-operative hypothyroidism.

 Sequela: a current condition that is a result of a previously occurring post-operative complication. Example: muscle wasting as a result of an intra-operative nerve injury that occurred 2 years earlier.

 Transient post-operative condition: transient conditions occurring during the post-operative period but are not necessarily regarded as post-operative complications. Examples include headache, nausea and vomiting, confusion, hypertension, electrolyte disturbances, etc. These conditions should only be coded as complications (using the 900-level ICD-9-CM diagnosis codes) when they are present at discharge, persist longer than would be considered normal by a clinician, or are documented by a physician that the condition is a complication of the surgery or other procedure.

A Challenge
It's the last category, transient post-operative condition, that presents the most variation in clinical condition, making it the most challenging to code appropriately. There is a vast difference in the majority of physicians' minds between a complication and an adverse reaction. A true complication, by this completely clinical standpoint, may reflect a misadventure (an error made by a physician or other care-giver) or other failing by the medical establishment. But adverse reactions are much more prevalent, which include those instances in which a patient experiences a reaction to a given treatment that happens through no fault of the caregiver, and may be expected in a certain percentage of all similar cases.

While an accidental laceration of a body site during surgery that bleeds extensively and requires treatment would be considered a complication, a patient experiencing transient acute blood loss anemia following hip replacement surgery (a well-known procedure that routinely causes anemia in a significant proportion of these patients) would be considered an adverse reaction unless prolonged or out of the ordinary. In some cases, the term "complication" may be applied only if the event led to a change in the treatment plan.

Another issue compounding the problem is that the majority of these conditions, whether a true complication or adverse reaction, are found in the ICD-9-CM diagnosis coding manual at section 996-999 (Complications of Surgical and Medical Care, Not Elsewhere Classified). The classification system includes both types of scenarios within this subchapter.

Varying Guidelines
Further adding to the confusion are varying guidelines related to the assignment of these 900-level codes. Hospital HIM coding departments should have specific internal coding guidelines that help clarify use of the codes but do not contradict national guidelines. For instance, a very common postoperative "complication," particularly following abdominal surgery, is a paralytic ileus or bowel obstruction. In some situations, when "postoperative ileus" is documented, the following two codes are assigned:

997.4 Digestive system complications

560.9 Unspecified intestinal obstruction

But there are conflicting coding guidelines throughout the country. Coding and DRG assignment is routinely monitored by regional quality improvement organizations (QIOs), which consist of physicians and other health care experts under contract with the Centers for Medicare and Medicaid Services (CMS) to monitor and improve care given to Medicare beneficiaries. One of these QIOs has provided the following coding instruction for postoperative ileus:

 "Paralytic ileus occurs commonly following abdominal or pelvic surgery and routinely lasts for 3 to 5 days. It's not coded unless it affects advancement of diet or requires intervention (i.e., reinsertion of NG tube)."

Hospitals that are in this particular QIO's region may see a smaller proportion of cases with the postoperative ileus codes assigned, not necessarily due to smaller incidence, but due to prevailing coding guidelines in that region. In fact, one of the few consistent complication coding guidelines throughout the country is the one indicating that the physician must state that the condition in question is directly related to the surgical or other procedure. The cause and effect must be clearly stated. Unfortunately, medical record documentation is not completely clear and concise, and coding staffs are left to either query the physicians (a practice that is limited in many hospitals due to the negative affect on accounts receivable (AR) and cash flow) or to try to interpret the less-than-perfect documentation. But the word "postoperative" may only refer to the fact that the events happened in sequence after the patient had undergone surgery.

It's easy to see how the application of these codes in a consistent manner is a definite challenge for many organizations. Coders should determine whether the diagnosis meets the UHDDS definition for "other diagnoses," which generally describes a condition that requires clinical evaluation, therapeutic treatment, diagnostic procedures, extended length-of-stay or increased nursing care and/or monitoring.

Classification in ICD-9-CM
Although the most recently released version of the ICD-9-CM Official Guidelines for Coding and Reporting (effective Oct. 1, 2007) contain specific guidelinesonly related to transplant complications, there are several other guidelines that are inherent in the ICD-9-CM system that should be followed:

Complications/adverse effects of care are classified in two distinct ways in ICD-9-CM:

 The assignment of codes in categories 001-799, which cover complications/adverse reactions related to specific anatomical sites or body systems. Examples include:

244.0         Postsurgical hypothyroidism

353.6         Phantom limb syndrome (following surgical amputation)

364.81       Intraoperative floppy iris syndrome [IFIS]

415.11       Iatrogenic pulmonary embolism and infarction

429.4         Functional disturbances following cardiac surgery

457.0         Postmastectomy lymphedema syndrome

512.1         Iatrogenic pneumothorax

518.4         Postoperative pulmonary edema

518.5         Pulmonary insufficiency following trauma and surgery

519.0X       Tracheostomy complications

569.6X       Colostomy and enterostomy complications

It should be noted that when assigning any of the codes above, corresponding codes from the 900-level categories should NOT be additionally assigned. Coders should review all INCLUDES and EXCLUDES notes carefully in these categories.

 The use of codes in categories 996-999, which classify complications involving multiple anatomical sites, body systems or prosthetic devices, implants and grafts. Examples include:

996.01 Mechanical complication due to cardiac pacemaker (electrode)

996.62 Infection and inflammatory reaction due to other vascular device, implant, and graft

996.77 Other complications (including pain) due to internal joint prosthesis

997.02 Iatrogenic cerebrovascular infarction or hemorrhage

997.61 Neuroma of amputation stump

998.2    Accidental puncture or laceration during a procedure

998.6    Persistent postoperative fistula

999.31 Infection due to central venous catheter

As noted above, it's extremely important that the coder review all INCLUDES and EXCLUDES notes carefully to determine which code most closely reflects the documentation in the medical record. Conditions that seem similar may actually be indexed in different ways. For instance, note that a post-amputation phantom limb syndrome is assigned to code 353.6, but a post-amputation neuroma is indexed to 997.61.

Transplant Complications
Transplant complications are somewhat different from a coding standpoint than the logic used for other complication/adverse reaction coding. Any disease in a transplanted organ that affects the functioning of the transplanted organ is considered a complication and a code from subcategory 996.8 should be assigned. Two codes should be assigned, one for the transplant complication, and one that identifies the complication itself. Pre-existing conditions or conditions that develop after the transplant are not coded as complications unless they affect the function of the transplanted organ. However, a kidney transplant patient with chronic kidney disease (CKD) shouldn't be classified with code 996.81 unless the physician documents transplant failure or rejection. Further information on this topic may be found in the ICD-9-CM Official Guidelines for Coding and Reporting, section I.C.17.f and also in Coding Clinic for ICD-9-CM, 3rd Quarter 1998, pp. 3-7.

Category 997
Many of the codes in category 997 (Complications affecting specified body systems, NEC) are fairly general in nature and should not be assigned if the Alphabetic Index provides a more specific code. Codes are provided for complications of the nervous, cardiac, peripheral vascular, respiratory, digestive and urinary systems, along with codes related to amputation stumps, vascular complications and those affecting other body systems. Once again, it must be stressed that the documentation must indicate that the condition is a complication of surgery.

Categories 998 and 999
Categories 998 and 999 reflect miscellaneous complications of procedures and of medical care not classified elsewhere. For the majority of these codes, an additional code is not necessary because the 998 or 999 code provides the detail of the complication in question. For example, codes for Non-healing surgical wound (998.83), Air embolism (999.1) or Infection due to central venous catheter (999.31) are stand-alone codes that do not require another code from categories 001-799 to be assigned.

Documentation and Review
Coding management should routinely review cases that contain complication codes on an ongoing basis and monitor the consistent assignment of these codes. It's very instructional to provide case examples in coding educational sessions, contrasting cases that are similar but should be coded differently, based on the specific medical record documentation in each. If some cases are in question, a physician liaison or other representative of the medical staff-or chair of the surgery department-should provide input on the classification of complications to ensure consistency, not only in code assignment, but also in the type and specificity of documentation required.

Everyone in the health care community would like the incidences of true patient complications and misadventures to be decreased as much as possible, but the reporting of these incidences must be accurate, fair and consistent across the country in order for the measurements to be meaningful and allow prevention strategies to work appropriately. One of the major reasons behind the implementation of the present on admission (POA) indicator assignment requirements (effective Jan. 1) is to allow CMS and other payers and regulators to determine whether a complication or other code indicating potential quality issues developed during the hospital encounter. As the data from this indicator assignment become available, it is inevitable that there will be increased scrutiny of all complication-related code assignment and reporting.


Test your knowledge on complication coding with the following quiz:

1. A 53-year-old patient who is status post kidney transplant was seen in the renal clinic for work-up of documented continuing chronic Stage 3 kidney disease. The appropriate diagnosis code(s) for this encounter is/are:

a. 996.81, 585.3, E878.0

b. 585.3, V42.0

c. 996.81, V42.0, 585.3, E878.0

d. V42.0, 585.9

2. A 49-year-old male patient who is status post hip replacement was admitted for treatment of a periprosthetic fracture of the prosthetic joint, sustained after minimal activity. The appropriate diagnosis code() for this encounter is/are:

a. 996.49, E878.1, V43.64

b. 820.8, E878.1, V43.64

c. 996.44, E878.1, V43.64

d. 996.66, E878.1, V43.64

3. A patient who is status post pacemaker implant was seen for work-up of weakness and palpitations in the chest and neck. He was found to have low cardiac output and pacemaker syndrome. The appropriate diagnosis code(s) for this encounter is/are:

a. 996.01, E878.1

b. 996.72, E878.1

c. 997.1, E878.1

d. 429.4, V45.01

4. A patient was admitted for treatment of abdominal wall cellulitis, extending from a gastrostomy site. The appropriate diagnosis code(s) for this encounter is/are:

a. 997.4, E878.0, 682.2

b. 996.69, E878.0

c. 536.41, 682.2

d. 536.41, 682.2, V44.1

This month's column has been prepared by Cheryl D'Amato, RHIT, CCS, director of HIM, and Melinda Stegman, MBA, CCS, clinical technical editor, Ingenix (, which specializes in the development and use of software and e-commerce solutions for managing coding, reimbursement, compliance and denial management in the health care marketplace.

Coding Clinic is published quarterly by the AHA.
CPT is a registered trademark of the AMA.


1. b. The documentation does not indicate that the ongoing chronic kidney disease is related to the kidney transplant, no transplant failure or rejection is indicated and so code 996.81 should not be assigned. The reason for the visit was the work-up for Stage 3 CKD, which is coded to 585.3. Code V42.0 is assigned to represent the kidney transplant status.

2. c. Code 996.44 is a very specific complication code that represents a peri-prosthetic fracture. An E code related to a surgical operation with implant of an artificial internal device should also be assigned, along with a V code specifying which specific joint was replaced in the past.

3. d. Refer to Coding Clinic, Nov-Dec 1985, p. 6, which describes Pacemaker syndrome, which is indexed in ICD-9-CM to code 429.4. Code V45.01 is assigned for the pacemaker status since this specific information is not contained in code 429.4.

4. c. All types of gastrostomy complications are now indexed to subcategory 536.4. Under code 536.41 there is a "Use additional code" note, instructing the coder to assign a separate code for the abdominal cellulitis (682.2). Code V44.1 is not assigned in this case because there is a complication and the artificial opening status codes are only assigned when there is no complication or management documented.

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