The role of diagnostic exams in population health and HCC reporting

May 22nd, 2019 / By Michael Malohifo’ou, RN, MBA

Diagnostic exams are an important way for hospitals and health systems to capture more complete, longitudinal patient information. Complete coding of diagnostic exams supports population health management and HCC reporting. Following current coding guidelines, providers should use all the tools available to them to deliver the highest degree of specificity at the time of exam reporting.

Healthcare payers have turned a critical eye toward any services that suggest overuse, waste or low value. One area of scrutiny is in ancillary services such as medical laboratory tests and diagnostic procedures. While the emphasis on value-based care is good—and necessary—the increased attention often implies that relevant information is only captured by a diagnostician during a face-to-face patient visit. This assumption isn’t true.

For example, take diagnostic tests ordered due to signs and/or symptoms. A patient is referred to a radiologist for a chest X-ray with a diagnosis of “cough.” The chest X-ray reveals a three centimeter peripheral pulmonary nodule. The radiologist should report a diagnosis of “pulmonary nodule” and may sequence “cough” as a secondary diagnosis.

In another example a patient is seen in the ER for chest pain. An EKG is normal, and the final diagnosis is chest pain due to suspected gastroesophageal reflux disease (GERD). The patient is told to follow-up with his primary care physician for further evaluation of the suspected GERD. The primary diagnosis code for the EKG should be chest pain. Although the EKG was normal, a definitive cause for the chest pain was not determined.

So, what guidelines should a physician and/or coder follow?

In the past, there has been some confusion about the meaning of “highest degree of specificity,” and in “reporting the correct number of digits.” In the context of ICD-10-CM coding, the highest degree of specificity refers to assigning the most precise ICD-10-CM code that most fully explains the narrative description of the symptom or diagnosis. The interpreting physician should code the ICD-10-CM code that provides the highest degree of accuracy and completeness for the diagnosis resulting from test, or for the sign(s)/symptom(s) that prompted the ordering of the test, following these guidelines:

  • 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.
  • If the results of the diagnostic test are normal or non-diagnostic, and the referring physician records a diagnosis preceded by words that indicate uncertainty (e.g., probable, suspected, questionable, rule out, or working), then the interpreting physician should not code the referring diagnosis. Rather, the interpreting physician should report the sign(s)or symptom(s) that prompted the study. Diagnoses labeled as uncertain are considered by the ICD-10-CM 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 should never be listed as primary diagnoses. If reported, incidental findings may be reported as secondary diagnoses by the physician interpreting the diagnostic test.
  • Unrelated and co-existing conditions/diagnoses may be reported as additional diagnoses by the physician interpreting the diagnostic test.

Here is one last example of the impact complete diagnosis coding can have on an outpatient claim. A patient is referred to a radiologist for a two-view chest X-ray because of a cough (CPT 71046). The result of the chest X-ray indicates the patient has unspecified bacterial pneumonia. During the performance of the diagnostic test, it was determined that the patient has essential hypertension NOS (I10) and diabetes mellitus with chronic complications (E11.21). The interpreting physician reports a primary diagnosis of unspecified bacterial pneumonia (J15.9). The interpreting physician may report the hypertension (R03.0) and diabetes mellitus (E11.21) as secondary diagnoses.

HCC captured in the outpatient diagnostic claims

The secondary diagnosis will not increase reimbursement for the test. However, by capturing diabetes mellitus in the claims data, the facility has captured an HCC that may not have otherwise been known to them—and one (in the above example) associated with a 0.371 weight toward the risk adjustment factor (RAF).

Michael Malohifo’ou, RN, is a Professional Consultant for 3M Health Information Systems.

Register for our Quality webinars.


For more information, see the following reference:

Department of Health & Human Program Memorandum
Services (DHHS) Centers for Medicare & Intermediaries/Carriers
SUBJECT: ICD-9-CM Coding for Diagnostic Tests
Medicaid Services (CMS) Transmittal AB-01-144
Date: SEPTEMBER 26, 2001