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Published on: January 26, 2024
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False-positive dengue non-structural protein 1 in pregnancy
Tonnii Sia1,2, Tze-Cheng Wong2, Yee-Chiing Ong2
1School of Public Health, Imperial College London, London SW7 2AZ, UK.
Transactions of the Royal Society of Tropical Medicine and Hygiene
|December 16, 2024
Summary
A false-positive dengue non-structural protein 1 (NS1) antigen test occurred in a pregnant patient. This highlights potential diagnostic challenges and the need for confirmatory testing in specific populations.
Area of Science:
- Infectious Diseases
- Clinical Diagnostics
- Obstetrics and Gynecology
Background:
- Dengue fever is a significant vector-borne illness causing substantial morbidity and mortality in endemic regions.
- Rapid diagnosis of dengue is crucial for timely treatment, with point-of-care tests (POCTs) utilizing non-structural protein 1 (NS1) antigen, IgM, and IgG antibodies being common.
- While dengue POCTs exhibit high specificity, occasional false-positive NS1 antigen results have been documented.
Purpose of the Study:
- To report the first documented case of a false-positive dengue NS1 antigen test in a pregnant individual.
- To discuss the diagnostic implications and potential causes of false-positive NS1 antigen results in pregnancy.
Main Methods:
- A case study of a 24-year-old pregnant female in her second trimester presenting with fever and cough.
- Dengue point-of-care testing (POCT) was performed, showing NS1 antigen positive, IgM negative, and IgG negative.
- Confirmatory real-time PCR for dengue and pan-Flaviviruses was conducted. Urine culture and treatment for urinary tract infection were also performed.
Main Results:
- The patient presented with symptoms suggestive of infection, and dengue POCT was positive for NS1 antigen but negative for IgM/IgG.
- The patient's symptoms resolved with antibiotic treatment for a confirmed urinary tract infection (Escherichia coli).
- Confirmatory molecular testing for dengue and flaviviruses was negative, and the NS1 antigen remained persistently positive for 18 days.
Conclusions:
- This case represents the first report of a false-positive dengue NS1 antigen test during pregnancy.
- The persistent NS1 positivity despite negative confirmatory tests suggests a potential cross-reactivity or other non-dengue related cause.
- Healthcare providers should consider differential diagnoses and confirmatory testing, especially in pregnant patients with atypical presentations or discordant POCT results.
