Misdiagnosis Due to False-Positive Detection of Pneumococcal Urinary Antigen
Introduction: The detection of pneumococcal antigens in urine is an alternative to gram staining, and their culture is central to the diagnosis of pneumococcal pneumonia. We present a case of the false-positive detection of urinary Streptococcus species pneumococcal antigen with a BinaxNOW test. Thi...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
SMC MEDIA SRL
2022-02-01
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| Series: | European Journal of Case Reports in Internal Medicine |
| Online Access: | https://www.ejcrim.com/index.php/EJCRIM/article/view/3198 |
| _version_ | 1811284680756953088 |
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| author | Kaori Notomi Taku Harada Takashi Watari Juichi Hiroshige Taro Shimizu |
| author_facet | Kaori Notomi Taku Harada Takashi Watari Juichi Hiroshige Taro Shimizu |
| author_sort | Kaori Notomi |
| collection | DOAJ |
| description | Introduction: The detection of pneumococcal antigens in urine is an alternative to gram staining, and their culture is central to the diagnosis of pneumococcal pneumonia. We present a case of the false-positive detection of urinary Streptococcus species pneumococcal antigen with a BinaxNOW test. This resulted in delayed diagnosis of a liver abscess.
Case description: A 70-year-old woman presented to the emergency department with a 1-day history of chills and difficulty walking. She had a fever and her physical examination was normal. Non-contrast chest computed tomography (CT) revealed a slight ground-glass opacity in the left lower lobe. Laboratory tests revealed liver injury and elevated C-reactive protein levels. A urinary pneumococcal antigen test was positive, and she was diagnosed with acute bronchopneumonia caused by Streptococcus pneumoniae. She was treated with ceftriaxone. However, abdominal contrast-enhanced CT performed the next day revealed portal vein thrombus and a left lobe liver abscess. Streptococcus constellatus was detected in a puncture specimen of the liver abscess. It was concluded that the positive urinary pneumococcal antigen test was a false-positive owing to Streptococcus infection.
Discussion: False-positive results might be explained by the presence of C-polysaccharide antigens in the cell wall of S. pneumoniae. The positive urinary antigen test together with the finding of slight ground-glass opacity in the left lung on chest CT initially led to misdiagnosis. False positives may result in misdiagnosis and unnecessary antimicrobial therapy.
Conclusion: The overuse of the pneumococcal urinary antigen tests can lead to false positives and misdiagnosis. |
| first_indexed | 2024-04-13T02:33:05Z |
| format | Article |
| id | doaj.art-ae6df456b0344059b132cf13367fbbee |
| institution | Directory Open Access Journal |
| issn | 2284-2594 |
| language | English |
| last_indexed | 2024-04-13T02:33:05Z |
| publishDate | 2022-02-01 |
| publisher | SMC MEDIA SRL |
| record_format | Article |
| series | European Journal of Case Reports in Internal Medicine |
| spelling | doaj.art-ae6df456b0344059b132cf13367fbbee2022-12-22T03:06:30ZengSMC MEDIA SRLEuropean Journal of Case Reports in Internal Medicine2284-25942022-02-0110.12890/2022_0031982733Misdiagnosis Due to False-Positive Detection of Pneumococcal Urinary AntigenKaori Notomi0Taku Harada1Takashi Watari2Juichi Hiroshige3Taro Shimizu4Division of General Medicine, Showa Medical University Hospital, Tokyo, Japan Division of General Medicine, Showa Medical University Hospital, Tokyo, Japan; Department of Diagnostic and Generalist Medicine, Dokkyo Medical University Hospital, Tochigi, JapanGeneral Medicine Centre, Shimane University Hospital, Shimane, JapanDivision of General Medicine, Showa Medical University Hospital, Tokyo, Japan General Medicine Centre, Shimane University Hospital, Shimane, JapanIntroduction: The detection of pneumococcal antigens in urine is an alternative to gram staining, and their culture is central to the diagnosis of pneumococcal pneumonia. We present a case of the false-positive detection of urinary Streptococcus species pneumococcal antigen with a BinaxNOW test. This resulted in delayed diagnosis of a liver abscess. Case description: A 70-year-old woman presented to the emergency department with a 1-day history of chills and difficulty walking. She had a fever and her physical examination was normal. Non-contrast chest computed tomography (CT) revealed a slight ground-glass opacity in the left lower lobe. Laboratory tests revealed liver injury and elevated C-reactive protein levels. A urinary pneumococcal antigen test was positive, and she was diagnosed with acute bronchopneumonia caused by Streptococcus pneumoniae. She was treated with ceftriaxone. However, abdominal contrast-enhanced CT performed the next day revealed portal vein thrombus and a left lobe liver abscess. Streptococcus constellatus was detected in a puncture specimen of the liver abscess. It was concluded that the positive urinary pneumococcal antigen test was a false-positive owing to Streptococcus infection. Discussion: False-positive results might be explained by the presence of C-polysaccharide antigens in the cell wall of S. pneumoniae. The positive urinary antigen test together with the finding of slight ground-glass opacity in the left lung on chest CT initially led to misdiagnosis. False positives may result in misdiagnosis and unnecessary antimicrobial therapy. Conclusion: The overuse of the pneumococcal urinary antigen tests can lead to false positives and misdiagnosis.https://www.ejcrim.com/index.php/EJCRIM/article/view/3198 |
| spellingShingle | Kaori Notomi Taku Harada Takashi Watari Juichi Hiroshige Taro Shimizu Misdiagnosis Due to False-Positive Detection of Pneumococcal Urinary Antigen European Journal of Case Reports in Internal Medicine |
| title | Misdiagnosis Due to False-Positive Detection of Pneumococcal Urinary Antigen |
| title_full | Misdiagnosis Due to False-Positive Detection of Pneumococcal Urinary Antigen |
| title_fullStr | Misdiagnosis Due to False-Positive Detection of Pneumococcal Urinary Antigen |
| title_full_unstemmed | Misdiagnosis Due to False-Positive Detection of Pneumococcal Urinary Antigen |
| title_short | Misdiagnosis Due to False-Positive Detection of Pneumococcal Urinary Antigen |
| title_sort | misdiagnosis due to false positive detection of pneumococcal urinary antigen |
| url | https://www.ejcrim.com/index.php/EJCRIM/article/view/3198 |
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