Understanding Primary Diagnosis Codes and Their Impact on Claim Denials

At Aculabs, we understand how crucial accurate diagnosis coding is to the success of claims submission and timely reimbursement. Unfortunately, we are seeing an increasing number of claim denials from payors due to the use of “invalid” primary diagnosis codes.

What Are Invalid Primary Diagnosis Codes?
An “invalid” primary diagnosis code typically refers to one that either:

– Does not meet the payer’s specific requirements for medical necessity.
– Is not supported by sufficient clinical documentation.
– Is outdated or improperly formatted.
– Does not align with the services provided or the patient’s condition.

These coding issues can result in delayed payments, rejections, or even additional administrative work to resolve the claim.

As well, the use of incorrect or invalid primary diagnosis codes is one of the leading causes of claim denials. Payers are increasingly focused on ensuring that diagnosis codes are accurate, specific, and aligned with their guidelines. When a primary diagnosis code is considered invalid, it may trigger an automatic denial, requiring the resubmission of corrected claims and potentially delaying reimbursement for services rendered.

Example for Understanding

For example, the ICD-10-CM code E11.9 is often considered invalid when used as the primary diagnosis for admitting a patient to the hospital for acute care. This code is classified as a Questionable Admission Code.

E11.9 indicates that a patient has type 2 diabetes mellitus, but no associated complications. Complications could include heart disease, blood vessel disease, nerve damage, eye damage, or skin conditions. When coding for diabetes, it’s essential to specify not only the type of diabetes but also factors like the degree of control, whether insulin is used, and any associated complications.

In cases where a patient is admitted for acute care, using E11.9 without complications typically does not justify the need for hospital admission under many payor guidelines, resulting in a denial.

Aculabs asks that nurse practitioners ensure timely and accurate documentation of ICD-10 diagnosis codes – as specified by the resident’s ordering physician – when placing a new lab order within our online web portal system.