Clinical Report: Healthcare Providers' Awareness of West Nile Virus Diagnostic Testing in the U.S.
Overview
A 2022 survey of 1502 U.S. healthcare providers revealed that only about one-quarter correctly ordered the appropriate laboratory tests for diagnosing West Nile virus (WNV) disease. Many providers selected unnecessary tests, leading to excess costs and potential diagnostic inefficiencies.
Background
West Nile virus is the most common mosquito-borne disease in the continental U.S., with most infections asymptomatic but some causing severe neuroinvasive disease. Accurate diagnosis relies primarily on WNV-specific IgM testing in serum or cerebrospinal fluid, with RT-PCR preferred for immunocompromised patients. Despite the importance of correct testing for patient management and public health, underdiagnosis occurs due to insufficient or inappropriate testing.
Data Highlights
Patient Scenario
Correct Test Only (%)
Correct + Unnecessary Tests (%)
Excess Testing Cost ($)
Patient A (Immunocompetent)
4.9
46.0
43,113
Patient B (Immunocompromised)
17.6
39.7
25,665
Both Patients Combined
0.4
26.0
58,244
Key Findings
Only 26% of providers selected the most appropriate diagnostic tests for both immunocompetent and immunocompromised patients, though many included unnecessary tests.
For the immunocompetent patient, only 4.9% chose solely the correct IgM serum and CSF tests; 46% included additional unnecessary tests, mainly RT-PCR.
For the immunocompromised patient, 17.6% selected only RT-PCR, the preferred test, while 39.7% added unnecessary IgM tests.
Internists were more likely to order appropriate tests compared to nurse practitioners, physician assistants, and family practitioners.
Providers in certain U.S. census divisions (East North Central, New England) were less likely to order correct tests than those in the Mountain division.
Group outpatient providers were less likely than inpatient providers to include IgM testing for immunocompetent patients.
Clinical Implications
These findings highlight a significant gap in healthcare provider knowledge regarding optimal WNV diagnostic testing, leading to unnecessary testing and increased healthcare costs. Targeted educational outreach is needed to improve appropriate test ordering, which can enhance clinical management, patient prognosis, and public health surveillance. Awareness of patient immune status is critical when selecting diagnostic tests for WNV.
Conclusion
The survey underscores the need for improved provider education on WNV diagnostic testing to reduce underdiagnosis and unnecessary testing. Enhancing provider knowledge will support better clinical decision-making and resource utilization in managing WNV disease.
References
CDC/2022 -- Understanding Healthcare Providers' Awareness of West Nile Virus Diagnostic Testing in the U.S.
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