The blood test to help diagnose Disseminated Gonococcal Infection (DGI) involves nucleic acid amplification testing (NAAT) or culture of a blood sample. However, diagnosis is definitively confirmed by isolating Neisseria gonorrhoeae from culture of other disseminated sites.
Here's a more detailed breakdown:
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Initial Testing (Blood): While blood cultures or NAAT of a blood sample may be performed, they aren't the most reliable method for confirming DGI.
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Definitive Diagnosis: The gold standard for diagnosing DGI is isolating Neisseria gonorrhoeae from a disseminated site. These sites can include:
- Blood: As mentioned above, but sensitivity can be low.
- Skin/Abscess(es): Culture or NAAT of skin lesions or any abscesses present.
- Cerebrospinal Fluid (CSF): If meningitis is suspected, a lumbar puncture is performed, and the CSF is cultured.
- Synovial Fluid: If septic arthritis is suspected, synovial fluid from the affected joint(s) is aspirated and cultured.
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Mucosal Site Testing: Often, the primary site of infection (e.g., urethra, cervix, pharynx, rectum) is tested concurrently via NAAT or culture, as this is often positive even when blood cultures are negative.
In summary, while a blood test (NAAT or culture) can support a diagnosis of DGI, the definitive diagnosis relies on isolating Neisseria gonorrhoeae from cultures of other disseminated sites in addition to testing mucosal sites.
