The landscape of medical diagnosis coding, already intricate, became even more complex with the advent of COVID-19. Globally, the World Health Organization (WHO) introduced two distinct Covid Diagnosis Codes to differentiate between cases confirmed by laboratory testing and those diagnosed clinically. However, the United States has adopted only one of these codes, creating a unique challenge for healthcare providers and medical coders in accurately documenting and billing for COVID-19 related services. Understanding this discrepancy and its implications is crucial for ensuring appropriate patient care and reimbursement.
Navigating the Coding Predicament in the US
The WHO established the following covid diagnosis codes:
- U07.1 – COVID-19, virus identified (lab confirmed)
- U07.2 – COVID-19, virus not identified (clinically diagnosed)
This dual system was designed to distinguish between cases with definitive laboratory confirmation (U07.1) and those diagnosed based on clinical evaluation in the absence of lab results (U07.2). While the WHO intended for both codes to be utilized, the United States swiftly implemented U07.1 as an off-cycle update to the ICD-10 code set. Notably, the US did not adopt U07.2 at the same time, leading to a situation where the description for U07.1 in the US omits “virus identified,” creating ambiguity about its precise application.
Alt text: Part 1 of a flowchart illustrating the COVID-19 diagnosis coding process, focusing on initial patient assessment and testing decisions.
This absence of a specific covid diagnosis code for clinically diagnosed cases in the US leaves physicians in a quandary. How should they accurately document and code for patients who present with COVID-19 symptoms but lack lab confirmation? Relying solely on symptom codes risks claim denials and exclusion of patients from vital disease registries. This is particularly significant because many payers waived cost-sharing for COVID-19 diagnosed patients. For claims to be recognized as COVID-19 related services, a covid diagnosis code is generally required. Furthermore, inclusion in disease registries is essential for effective patient follow-up, especially as serologic testing becomes more prevalent.
The sensitivity of initial COVID-19 diagnostic RT-PCR tests has been reported to be around 70% with a single respiratory swab. This means that some patients with clinical presentations strongly suggestive of COVID-19 may initially test negative, only to test positive on subsequent tests. These individuals should still be accurately diagnosed and coded as having COVID-19, even with initial negative lab results.
Alt text: Part 2 of the COVID-19 diagnosis coding flowchart, detailing the steps for patients with suspected COVID-19 and negative initial RT-PCR test results.
The emergence of serologic (antibody) testing adds another layer of complexity to covid diagnosis code assignment. When the ICD-10 code U07.1 was initially introduced, RT-PCR testing was the primary diagnostic tool. Now, serologic tests are more readily available. The CDC guidelines suggest that serologic testing can be valuable for diagnosing COVID-19 in patients presenting later in their illness (9 to 14 days after symptom onset). In such cases, antibody testing alongside RT-PCR testing can enhance diagnostic sensitivity. A positive serologic test indicates a past or present COVID-19 infection, but false positives are possible, meaning serology alone shouldn’t be the sole basis for a COVID-19 diagnosis.
Consider a patient with clinical symptoms and potential exposure, but a negative RT-PCR test. If serologic testing reveals IgM (-) and IgG (+), should they receive a covid diagnosis code? Similarly, what about an asymptomatic patient with no known exposure, a negative RT-PCR test, but IgM (-) and IgG (+) serology? These scenarios raise questions about the need for a new ICD-10 code to denote prior COVID-19 infection or exposure identified through serology.
Alt text: Part 3 of the diagnostic flowchart, focusing on the interpretation of serologic test results (IgM and IgG antibodies) in relation to COVID-19 diagnosis.
Recommended Coding Practices in the US
Given the absence of a dedicated covid diagnosis code for clinically diagnosed COVID-19 in the US coding system, healthcare providers are primarily left with U07.1 – COVID-19. The CDC’s National Center for Health Statistics (NCHS), for vital statistics reporting, has confirmed that U07.1 can be used for both lab-confirmed and clinically diagnosed COVID-19 deaths. Furthermore, broader CDC guidance on coding for living patients provides room for interpretation. The CDC states, “Code only a confirmed diagnosis of the 2019 novel coronavirus disease (COVID-19) as documented by the provider, documentation of a positive COVID-19 test result, or a presumptive positive COVID-19 test result. In this context, ‘confirmation’ does not require documentation of the type of test performed; the provider’s documentation that the individual has COVID-19 is sufficient.” This phrasing, “as documented by the provider,” can be interpreted to encompass clinical diagnosis made by the physician.
Alt text: Part 4 of the COVID-19 coding algorithm flowchart, guiding physicians on final diagnosis and coding based on clinical evaluation and test results.
Various diagnostic algorithms can be employed for diagnosing COVID-19. When making a clinical diagnosis, particularly without a positive test, physicians should consider the prevalence and incidence of COVID-19 in their local community. This localized epidemiological context is crucial for informed clinical decision-making and appropriate covid diagnosis code assignment. The provided flowchart offers a helpful framework for navigating these complexities and ensuring accurate coding in diverse healthcare settings. Remember that adapting coding algorithms to specific geographic locations and evolving prevalence rates is essential for maintaining coding accuracy and reflecting the dynamic nature of the pandemic.
