Diagnosis Radiology Coding Guidelines

This blog first appeared on RadRx.

With radiology services coming under intense scrutiny for medical necessity, it is more important than ever to ensure that documentation for radiology exams is complete. This includes ensuring that diagnosis coding is done in accordance with the official coding guidelines and the Center for Medicare & Medicare Services (CMS) policy.

Although many claims are being paid when initially submitted, post payment reviews are resulting in providers having to return monies to Medicare and other third-party payers. This can be avoided with a proper medical necessity screening process.

The right medical necessity screening process ensures that all pertinent clinical information is received prior to a service being rendered. It also verifies compliance in coding practices after an exam is performed and documented.

1. Document Review for Determining Diagnosis Code

There are two key documents for review. Although each is a viable source document for selecting a diagnosis code for the encounter, utilizing only one of these two documents to select procedure and diagnosis codes can result in unnecessary coding compliance risks for any provider of services.

    • Test order with accompanying signs/symptoms
    • Radiology report containing the final written interpretation

At first glance it may appear that diagnosis coding for diagnostic radiology exams is straightforward, it actually can be quite challenging. In many cases, the documentation that must be reviewed prior to assigning a diagnosis code may be unavailable, unclear or contradictory.

2. The Diagnostic Test Order

An encounter for radiology services begins with a test order from the referring (ordering physician) which is then taken to an imaging center, hospital or other provider of diagnostic imaging services.

A complete and accurate test order is crucial to coding compliance because payment for services by Medicare is made only for those services that are reasonable and necessary. Furthermore, CMS charges the referring physician with the responsibility of documenting medical necessity as part of the Medicare Conditions of Participation (42 CFR 410.32).

The Balanced Budget Act of 1997 reiterates this requirement in Section 4317(b) where it states that the ordering physician must provide signs/symptoms or a reason for performing the test at the time it is ordered. If the referring physician indicates a “rule out”, he/she must also include signs/symptoms prompting the exam for ruling out that condition.

In the event this information is missing, the ordering physician should be contacted for this information before proceeding with the exam.

Since medical necessity is determined by those signs/symptoms provided by the ordering physician, it is vital to have this information at the time of final coding even when the radiology report identifies and abnormal finding or condition. This information is key in helping to determine whether or not a finding is incidental or related to the presenting signs/symptoms.

Furthermore, a test ordered to “rule out” a specific condition is considered a screening exam in the eyes of Medicare and would need to be coded as such in the absence of documented signs/symptoms, with a screening code assigned as the primary diagnosis and any findings assigned as additional diagnoses.

3. The Radiology Report

While the test order may determine medical necessity and initially drive the encounter, review of the final radiology report holds the key to determining the correct diagnosis codes for an encounter.

Radiology reports contain four main sections:

    • clinical indications
    • technique
    • summary of findings
    • impression and final interpretation

The clinical indications listed on the report should be those signs or symptoms provided by the referring physician that prompted the ordering of the test.

The radiologist’s final interpretation, the impression, may list multiple conditions and is the final piece of the puzzle in choosing a primary diagnosis code.

Additionally, careful review of the clinical indications will help determine whether or not certain conditions mentioned in the findings section, or in the impression, are clinically significant or simply incidental findings.

4. Choosing the Primary Diagnosis

The ICD-10-CM Official Guidelines for Outpatient Coding and Reporting contains guidelines specific to patients receiving diagnostic services only:

“For patients receiving diagnostic services only during an encounter/visit, sequence first the diagnosis, condition, problem, or other reason for encounter/visit shown in the medical record to be chiefly responsible for the outpatient services provided during the encounter/visit. Codes for other diagnoses (e.g., chronic conditions) may be sequenced as additional diagnoses.

For encounters for routine laboratory/radiology testing in the absence of any signs, symptoms, or associated diagnosis, assign Z01.89. Encounter for other specified ICD-10-CM Official Guidelines for Coding and Reporting FY 2018 Page 110 of 117 special examinations. If routine testing is performed during the same encounter as a test to evaluate a sign, symptom, or diagnosis, it is appropriate to assign both the Z code and the code describing the reason for the non-routine test.

For outpatient encounters for diagnostic tests that have been interpreted by a physician, and the final report is available at the time of coding, code any confirmed or definitive diagnosis(es) documented in the interpretation. Do not code related signs and symptoms as additional diagnoses”.

Coding Rules Summary: Diagnosis Coding for Radiology Exams

Confirmed Diagnosis Based on Results of Test

If the physician has confirmed a diagnosis based on the results of the diagnostic test, the physician interpreting the test should code that diagnosis. The signs and/or symptoms that prompted ordering the test may be reported as additional diagnoses if they are not fully explained or related to the confirmed diagnosis.

Signs or Symptoms

If the diagnostic test did not provide a diagnosis or was normal, the interpreting physician should code the sign(s) or symptom(s) that prompted the treating physician to order the study.

Diagnosis Preceded by Words that Indicate Uncertainty

If the referring physician provides a diagnosis preceded by words that indicate uncertainty (e.g., probable, suspected, questionable, rule out, or working), the uncertain diagnosis should not be coded.

Furthermore, if the results of the diagnostic test are normal or a definitive diagnosis has not been made by the radiologist, signs/symptoms prompting the ordering of the test should be identified and reported.

Diagnoses labeled as uncertain are considered by the ICD10CM Coding Guidelines as unconfirmed and should not be reported. This is consistent with the requirement to code the diagnosis to the highest degree of certainty.

Incidental Findings

Incidental findings should never be listed as primary diagnoses. If reported, incidental findings may be reported as secondary diagnoses. It is recommended to report any incidental findings that may warrant additional follow-up studies.

Unrelated Coexisting Conditions/Diagnoses

Unrelated and coexisting conditions/diagnoses may be reported as additional diagnoses by the physician interpreting the diagnostic test.

Diagnostic Tests Ordered in the Absence of Signs and/or Symptoms

When a diagnostic test is ordered in the absence of signs/symptoms or other evidence of illness or injury, the testing facility or the physician interpreting the diagnostic test should report the screening code as the primary diagnosis code. Any condition discovered during the screening should be reported as a secondary diagnosis.

Reviewing the Source Documents & Choosing the Primary Dx Code

Armed with the test order, radiology report and all of the coding guidelines, there are a few stages to assembling all of the pieces of the puzzle.

5 Steps for Selecting the Primary Dx Code

  1. Review the information documented under the “impression” for any definitively diagnosed conditions.
  2. Review the clinical indications to determine if those conditions listed in the impression are related to the exam, or unrelated incidental findings for the exam ordered. The clinical indications on the report should match those on the order from the referring physician.
  3. Review the summary of findings in the body of the report if necessary to clarify the diagnostic information provided in the impression. Sometimes this may be helpful in adding specificity for coding a particular condition.

Exercise caution in using information documented only in the summary of findings and not documented in the impression. Often the radiologist will comment on everything that he sees visualized on the images, but not all findings noted are clinically significant for the exam being performed.

  1. Choose the primary diagnosis code based on the guidelines in the section above title “Choosing the Primary Diagnosis” after considering and determining all pertinent findings in the radiology report.
  2. Assign diagnosis codes for any other additional pertinent findings. Incidental findings may be coded after all clinically significant findings are reported. Incidental findings are abnormal findings not specifically related to why the exam was performed but discovered during the exam.

A few common examples of findings that might be considered incidental are:

    • MRI Brain: Atrophy or ischemic changes in the elderly
    • CT Abdomen:  Fatty liver or liver cyst
  • CT Pelvis:  Diverticulosis

The following examples illustrate incidental findings:

    • A patient is referred for an abdominal ultrasound due to jaundice. After review of the ultrasound, the radiologist discovers the patient has an aortic aneurysm. The primary diagnosis is jaundice and the aortic aneurysm may be reported as a secondary diagnosis.
    • A patient is referred for a chest x-ray because of wheezing. The x-ray is normal except for scoliosis and degenerative joint disease of the thoracic spine. The primary diagnosis is wheezing since it was the reason for the patient’s visit. The other findings may be reported as additional diagnoses.
  • A patient is referred for an MRI of the lumbar spine with a diagnosis of L-4 radiculopathy. The MRI reveals degenerative joint disease at L1 and L2. The primary diagnosis is radiculopathy and the degenerative joint disease of the spine may be reported as an additional diagnosis.

It should never be assumed that any particular condition is always incidental. What is considered incidental for one patient and one study, may not be considered incidental for another patient and another study. When there is difficulty in determining whether or not a finding is incidental or whether or not it should be reported, it is prudent to query the radiologist.

This blog post first appeared on RadRx.  

Stacie L. Buck, RHIA, CCS-P, RCC, CIRCC, AAPC Fellow

President & Senior Consultant, RadRx

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