How to be a great HCC coder? Know ICD-10-CM Official Guidelines for Coding and Reporting

During an encounter:

• Code conditions assessed and managed.
• If treatment of an acute or chronic problem is affected by an ongoing condition, note that, and add the ongoing condition to the claim form.
• If the condition has a manifestation or complication, or is defined by severity or stage, select the specific code.
• Add status codes and social determinants of health.
• All conditions reported should be supported in the medical record.

Use documentation on the day of the encounter found in the history of the present illness/review of systems, exam and assessment and plan.

Do not select codes from the problem list that were not evaluated at the encounter.

Code conditions annually.

Document: condition—status—plan

For patients with multiple complications of the same condition, there is no requirement that there are separate plans.

Example: Diabetes with three complication codes

Diabetes with hyperglycemia

• Clinician documents status of diabetes and medications. Could include treatment for other manifestations.

Diabetes with retinopathy

• Primary care practitioner will probably not have a specific plan related to the retinopathy. The treatment plan for the diabetes covers this.

Diabetes with skin ulcer

• There would likely be a plan for this condition, but it can be documented under the code for diabetes with hyperglycemia or here.

Conditions indicated in the index using the word “with” are assumed to be related unless the clinician notes otherwise.

Citations:

“Code all documented conditions which coexist at the time of the visit that require or affect patient care or treatment.” 

ICD-10-CM General Guidelines 202 §IV.J.

“The assignment of a diagnosis code is based on the provider’s diagnostic statement that the condition exists. The provider’s statement that the patient has a particular condition is sufficient. Code assignment is not based on clinical criteria used by the provider to establish the diagnosis.”

ICD-10-CM General Guidelines 2024 §I.A.19.

“Medical history alone may not be used as a source of diagnoses for risk adjustment purposes. For a chronic condition to be accepted for risk adjustment, the patient must have a face-to-face visit each year with a provider/physician who assesses and documents that condition.”

CMS Risk Adjustment 101 Participant Guide, page 17.

“Co-existing conditions include chronic, ongoing conditions such as diabetes, congestive heart failure, atrial fibrillation, chronic obstructive and pulmonary disease. These diseases are generally managed by ongoing medication and have the potential for acute exacerbations if not treated properly, particularly if the patient is experiencing other acute conditions. It is likely that these diagnoses would be part of a general overview of the patient’s health when treating co-existing conditions for all but the most minor of medical encounters.”  

CMS 2008 Risk Adjustment Data Technical Assistance 6.6

“A code can be assigned on the basis of the evaluation and clinical findings/treatment.”

CMS 2008 Risk Adjustment Data Technical Assistance 7-14

Unacceptable documentation includes a list of patient conditions.

CMS 2008 Risk Adjustment Data Technical Assistance 7-15

OIG

Issued a series of reports based on the focus in the OIG Work Plan of Medicare Advantage Organizations diagnosis coding.

• Focused on the same conditions across MAO plans.

“Using data mining techniques and discussions with medical professionals, we identified diagnoses that were at higher risk for being miscoded and consolidated those diagnoses into specific groups. For this audit, we focused on seven high-risk groups.”  May 2023 A-03-20-00001

The following are excerpts from multiple reports by the OIG findings. All descriptions below from the OIG report.

Acute stroke

An enrollee received one acute stroke diagnosis (that mapped to the HCCs for Ischemic or Unspecified Stroke) on one physician claim during the service year but did not have that diagnosis on a corresponding inpatient or outpatient hospital claim. In these instances, a diagnosis of history of stroke (which does not map to an HCC) typically should have been used.

Acute MI

Acute heart attack: An enrollee received one diagnosis that mapped to either the HCC for Acute Myocardial Infarction or to the HCC for Unstable Angina and Other Acute Ischemic Heart Disease (Acute Heart Attack HCCs) on only one physician or outpatient claim during the service year but did not have that diagnosis on a corresponding inpatient hospital claim (either within 60 days before or 60 days after the physician or outpatient claim). In these instances, a diagnosis for a less severe manifestation of a disease in the related-disease group typically should have been used.

Embolism

An enrollee received one diagnosis that mapped to either the HCC for Vascular Disease or to the HCC for Vascular Disease with Complications (Embolism HCCs) during the service year but did not have an anticoagulant medication dispensed on his or her behalf. An anticoagulant medication is typically used to treat an embolism. In these instances, a diagnosis of history of embolism (an indication that the provider is evaluating a prior acute embolism diagnosis, which does not map to an HCC) typically should have been used.

Vascular claudication

Vascular claudication: An enrollee received one diagnosis related to vascular claudication (that mapped to the HCCs for Vascular Disease) during the service year but had not received one of these diagnoses during the 2 preceding years and had medication dispensed on his or her behalf that is frequently dispensed for a diagnosis of neurogenic claudication. In these instances, the diagnosis related to vascular claudication may not be supported in the medical records.

Cancer

Four types of cancer reviewed: breast, lung, prostate, colon

Sample from OIG report: For 21 enrollee-years, the medical records indicated in each case that the individual had previously had colon cancer, but the records did not justify a colon cancer diagnosis at the time of the physician’s service.

Major depressive disorders

Major depressive disorder: An enrollee received one major depressive disorder diagnosis (that mapped to the HCCs for Major Depressive, Bipolar, and Paranoid Disorders) during the service year but did not have an antidepressant medication dispensed on his or her behalf. In these instances, the major depressive disorder diagnoses may not be supported in the medical records.

Keying errors

Potentially miskeyed diagnosis codes: An enrollee received multiple diagnoses for a condition but received only one—potentially miskeyed—diagnosis for an unrelated condition (that mapped to a possibly unvalidated HCC). For example, ICD-9 diagnosis code 250.00 (which maps to the HCC for Diabetes Without Complication) could be transposed as diagnosis code 205.00 (which maps to the HCC for Metastatic Cancer and Acute Leukemia and in this example would be unvalidated). Using an analytical tool that we developed, we identified 832 scenarios in which diagnosis codes could have been miskeyed because numbers were transposed, or other data-entry errors occurred that could have resulted in the assignment of an unvalidated HCC.

Compliance Issues

	Do not use	Use
Patient seen in office, follow up for TIA	G45.9 Transient cerebral ischemic attacks and related syndromes (Does not risk adjust)	Z86.73 Personal history of transient ischemic attack (TIA), and cerebral infarction without residual deficits
Patient seen in office in follow up after a stroke	I63 Cerebral infarction	Use I69 Sequelae of cerebrovascular disease or Z86.73 (above)
	Do not use	Use
Patient seen and noted to have “history of XXX cancer” but no current evidence of disease or current treatment	Code indicating malignant neoplasm, starting with the letter C	Code from category Z85.-, Personal history of malignant neoplasm
	Do not use	Use
Patient seen > 28 days after an acute MI	I20.-, I21.-, I22.- Current MI	I25.2 Old myocardial infarction

Be careful about “history of” notations in records. Often, the clinician uses that term for current conditions, such as “she has a history of hypertension” when the patient has that condition. Ask if unclear.

• Don’t use the code for the condition when it is a past event, such as stroke or TIA, above.
• Only use malignant neoplasm codes if the patient has evidence of the disease or is currently being treated for the disease. Active treatment includes surgery, chemotherapy, radiation therapy and adjuvant hormonal therapies. If the patient has no evidence of disease and there isn’t active treatment, use personal history of malignant neoplasm. There isn’t a cutoff date “after a year” or “when surveillance ends.”