Investigations

1st investigations to order

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Result
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Nonculture testing using NAAT is available and is generally recommended as a first-line method of testing.[23][47] The Association of Public Health Laboratories and the Centers for Disease Control and Prevention recommend NAAT for the detection of genital tract infections with gonorrhea without routine repeat testing for positive results.[46][48]

Useful for urine, urethral, cervical, and vaginal specimens. However, it is not Food and Drug Administration-approved for use in nongenital sites (pharyngeal and rectum). Individual laboratories can perform NAAT at nongenital sites if they satisfy regulations for Clinical Laboratory Improvement Amendments compliance before reporting results.[46][48]

Most sensitive method to detect gonorrhea but has less than 100% specificity, particularly with pharyngeal and rectum specimens.

Samples for NAAT can be collected by the clinician/healthcare provider or the patient (self-collected).[23] Self-collected specimens sent for NAAT have been found to be noninferior to clinician-collected specimens, although local laboratory validation of this collection method should be conducted.[49][50]

NAAT for chlamydial infection is also recommended.[23]

Result

positive for gonorrhea

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Result
Test

Urethral, endocervical, rectal, pharyngeal, blood, synovial fluid, cerebrospinal fluid, or conjunctival specimen can be used.

Definitive diagnostic test but has deficiencies in sensitivity with pharyngeal and rectal sites: sensitivity of culture for the pharynx is about 50%.[58]

It is the only available method to test for antimicrobial sensitivities.

Culture is the only Food and Drug Administration-approved method for testing rectum and pharyngeal specimens, and it may be the only available option in some regions.[23]

Culture of swabs for chlamydial infection may also be requested.

Result

positive chocolate agar culture

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Result
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Useful if patient has no urethral discharge.

Provides a presumptive diagnosis of urethritis and guides differential and further investigation.[23]

Result

positive leukocyte esterase

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Result
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Useful if patient has no urethral discharge.

Confirms urethritis and guides differential and further investigation.

Strongly suggests gonorrhea if organism seen. But does not rule out gonorrhea if organisms not seen.[59]

Result

≥10 WBC per high-power field or ≥2 WBC per oil immersion field; intracellular gram-negative diplococci in polymorphonuclear leukocytes

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Result
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Confirms urethritis and guides differential and further investigation.com.bmj.content.model.Caption@653b2da[Figure caption and citation for the preceding image starts]: Photomicrograph revealing the histopathology in an acute case of gonococcal urethritis using gram-stain techniqueCDC/ Joe Millar [Citation ends].

Strongly suggests gonorrhea if organism seen. But does not rule out gonorrhea if organisms not seen.[59]

Result

intracellular gram-negative diplococci in polymorphonuclear leukocytes

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Result
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Routine to rule out HIV. Time to HIV seropositivity with a third-generation enzyme immuno assay (EIA) can be >21 days.

Result

may be positive

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Result
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Routine to rule out syphilis. A venereal disease research laboratory (VDRL) test or serum rapid plasma reagin (RPR) test can take up to 3 months to become positive. Some laboratories may perform a reverse sequence screening algorithm that uses a serologic test before the RPR.

Result

may be positive

Investigations to consider

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Result
Test

Highly specific for pelvic inflammatory disease. Useful in presence of chronic ascending infection resulting in tubo-ovarian abscess.

Result

thickening of endometrium or tubes; fluid in the tubes or abscess

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Result
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Highly specific for pelvic inflammatory disease (PID). When diagnosis of PID is uncertain or ultrasound is equivocal, either a CT or MRI may be performed, if available.

Result

inflammatory changes of fallopian tubes and ovaries; abnormal fluid collection; thickened ligaments

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