TOP 6 CODING ERRORS - Humana

What is coding errors


Documentation errors in which a treatment is miscoded or the codes used to describe procedures do not match those used to identify the diagnosis.

Humana Identifies Top Coding Errors

Coding errors can result in reduced or delayed reimbursement and contribute to an incomplete record of a Humana member’s health. Humana offers health care providers and their coding staff the following information on the most common coding errors and guidelines on how to avoid them:


Incorrectly using current versus historical.

Avoid using the phrase “history of” to describe current or chronic conditions that are still present, active and ongoing. A medical condition described as “history of” means the condition was in the past and no longer exists. Coders should not code such conditions as current when it is not clear that the condition still exists. For example:

A patient has a current abdominal aortic aneurysm that is monitored with yearly abdominal ultrasounds to ensure the aneurysm is not increasing in size. The medical record documents “history of abdominal aortic aneurysm” with no other information. The medical coder should not code this condition as a current diagnosis, since it is documented as historical and not current.


It is equally important for health care providers to refrain from documenting past conditions that no longer exist as if they are current. For example:

The final assessment includes “cerebrovascular accident (CVA).” A diagnosis code may be erroneously assigned for this condition as if it is current (434.91); when in reality, the patient experienced a cerebrovascular accident two years ago and has no residual deficits (V12.54). In this scenario, the condition really should have been documented as “history of cerebrovascular accident two years ago with no residual deficits.”

A patient with a history of prostate cancer that has been eradicated in the past presents to the office for a six-month follow-up visit for evaluation, examination and lab test (prostate specific antigen, or PSA) to monitor for recurrence. The assessment section states “prostate cancer,” which classifies to code 185 (the code for current prostate cancer). This is an error in documentation that results in an error in ICD-9-CM coding. The correct way to document this condition is “history of prostate cancer – PSA shows no evidence of cancer recurrence. Will continue to monitor PSA every six months to check for recurrence.” History of prostate cancer classifies to code V10.46, personal history of malignant neoplasm of prostate.


Failure to code to the highest level of specificity.

Medical coders must carefully review the entire medical record with attention to the details of a specific diagnosis description; for example, the coder must look for documentation of:

The specific site or location on the body or within a body part

The specific type or stage of the condition

Whether the condition is linked to another condition in a cause-and-effect relationship. It is incorrect to code two conditions as linked in a cause-and-effect relationship when the medical record documentation does not link them. The medical coder is not allowed to make assumptions and must code the conditions exactly as they are documented within the medical record. It is also incorrect to code two conditions separately when the medical record documentation links them in a cause-and-effect relationship. For example:

The medical record documents a diagnosis of “diabetes mellitus type 2, controlled” and separately documents a diagnosis of “peripheral neuropathy.” Correct coding is:

250.00: Diabetes mellitus without mention of complication, type II or unspecified type, not stated as uncontrolled.
356.9: Unspecified hereditary and idiopathic peripheral neuropathy.

The medical record documents a diagnosis of “diabetes mellitus type 2, controlled with peripheral neuropathy.” Correct coding is:

250.60: Diabetes with neurological manifestations, type II or unspecified type, not stated as uncontrolled.
357.2: Polyneuropathy in diabetes.

Another example of lack of specificity in coding is:
The final assessment documents simply “breast cancer”; so, the coder assigns 174.9, Malignant neoplasm of breast (female), unspecified site. However, upon closer review, it is noted that the History of Present Illness documents a biopsy one week ago of a lump found in the upper, inner quadrant of the right breast, which was positive for adenocarcinoma. The most accurate ICD-9-CM code for this documentation is 174.2, Malignant neoplasm of upper-inner quadrant of female breast.



Coding uncertain diagnoses as confirmed (in the outpatient setting). 

Coders should be careful not to code an uncertain diagnosis as a confirmed diagnosis. The ICD-9-CM Official Guidelines for Coding and Reporting (Section IV. Diagnostic Coding and Reporting Guidelines for Outpatient Services, I. Uncertain diagnosis) advises as follows:

Do not code diagnoses documented as “probable,” “suspected,” “questionable,” “rule out,” “working diagnosis” or other similar terms indicating uncertainty. Rather, code the condition(s) to the highest degree of certainty for that encounter/visit, such as symptoms, signs, abnormal test results or other reason for the visit.



Misinterpretation of abbreviations and acronyms.

Best documentation practice is for health care providers to limit the use of abbreviations or acronyms or avoid them altogether. However, many health care providers freely use abbreviations and acronyms. Some standard abbreviations and acronyms have multiple meanings. The meaning of the abbreviation or acronym can often be determined based on context, but this is not always true. Thus, coding errors result. The following list includes examples of abbreviations and acronyms with multiple meanings that can lead to incorrect code assignment:

AF — atrial fibrillation, atrial flutter.
MI — myocardial infarction, mitral insufficiency, mitral incompetence.
RA — rheumatoid arthritis, refractory anemia.
MDD — major depressive disorder, manic depressive disorder.

Best practice documentation includes the following:
The initial notation of an abbreviation or acronym should be spelled out in full with the acronym in parentheses. For example, “myocardial infarction (MI)” or “rheumatoid arthritis (RA).”
Subsequent mention of the condition can be made using the acronym.
The diagnosis should again be spelled out in full in the final impression or plan.




Applying a clinical interpretation to medical record documentation.

Coders should avoid reading into or clinically interpreting medical information or assigning a diagnosis that is not documented by the treating health care provider. For example:
The final impression in a medical record is chronic kidney disease (with no stage specified). The medical coder notes that the record documents a glomerular filtration rate (GFR) of 45. Since the coder knows a GFR within the 30 to 59 range equates to stage 3, code 585.3, chronic kidney disease stage 3, is assigned. This is not correct, as there is no documentation of stage 3 in the record. It is the health care provider’s responsibility to document the stage of chronic kidney disease. When no stage is documented, code 585.9, chronic kidney disease, unspecified, must be assigned.


Failure to code historical and status conditions 

The ICD-9-CM Official Guidelines for Coding and Reporting read, “Personal and family history codes are acceptable on any medical record, regardless of the reason for the visit. A personal history of an illness, even when no longer present – or a family history of a condition – both represent important information that can influence patient care, treatment or management.”

Other excerpts from the ICD-9-CM Official Guidelines for Coding and Reporting include:
Personal history codes explain a patient’s past medical condition that no longer exists and is not receiving any treatment, but has the potential for recurrence and therefore may require continued monitoring (with the exceptions of personal history of allergy to medicinal agents or to substances other than medicinal agents, e.g., a person who has had an allergic episode to a substance or food in the past should always be considered allergic to the substance).

Family history codes are used when a patient has a family member with a particular disease that causes the patient to be at higher risk of also contracting the disease.

Personal history codes may be used in conjunction with follow-up codes to explain the need for a test or procedure.

Family history codes may be used in conjunction with screening codes to explain the need for a test or procedure.

Status codes indicate that a patient is a carrier of a disease, has the sequelae (residual of a past disease or condition)or has another factor influencing his or her health status. An example includes the presence of prosthetic or mechanical devices resulting from past treatment. A status code is informative, because the status may affect the course of treatment and its outcome. A status code is distinct from a history code, which indicates that the patient no longer has the condition.

A status code should not be used with a diagnosis code from one of the body system chapters if the diagnosis code includes the information provided by the status code. For example, code V42.1, heart transplant status, should not be used with code 996.83, complications of transplanted heart. The status code does not provide additional information. The complication code indicates that the patient is a heart transplant patient.