Supporting the diagnosis of bacterial vaginosis
Conventional Gram Stain Procedure and Nugent Scoring System
Bacterial Vaginosis Gram stain
Bacterial vaginosis
Varies
Question ID | Description | Answers |
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Q00M0087 | Specimen Source |
Preferred:
Specimen Type: Vaginal swab
Supplies: Culturette (BBL Culture Swab) (T092)
Container/Tube: Culturette swab (Dacron or rayon swab with aluminum or plastic shaft with either Stuart or Amies medium)
Specimen Volume: Entire collection
Specimen Stability Information:
ESwab: Refrigerated (preferred) 7 days/Ambient 7 days
Culturette Swab: Ambient (preferred) 7 days/Refrigerated 7 days
Acceptable:
Specimen Type: Prepared microscope slide
Source: Vaginal swab
Supplies: Culturette (BBL Culture Swab) (T092)
Collection Container/Tube: Culturette swab (Dacron or rayon swab with aluminum or plastic shaft with either Stuart or Amies medium)
Submission Container/Tube: Slide container
Specimen Volume: Slide
Collection Instructions: Apply original sample to surface of standard microscope slide using appropriate application method (determined by consistency of specimen type) to assure adequate transfer of specimen onto slide. Allow specimen to dry and then methanol or heat-fix the slide. Place in slide container for transport.
If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.
Dry swab | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Varies | Varies |
Supporting the diagnosis of bacterial vaginosis
Bacterial vaginosis (BV) occurs when normal vaginal/urogenital microbiota (predominance of Lactobacillus species) is replaced by other bacteria (Gardnerella vaginalis, Atopobium vaginae, etc). Clinical signs of BV (Amsel's criteria) include increased vaginal pH (>4.5); thin, gray, homogeneous discharge; fishy malodor enhanced by adding potassium hydroxide; and clue cells (epithelial cells covered with bacteria that obliterate the cell border). The standard scoring system termed the "Nugent score" is a technique for assessing bacterial vaginosis using microscopic examination of a Gram-stained smear of vaginal discharge.
One of the 3 following reports dependent on the weighted sum balance of Lactobacillus, Gardnerella/Bacteroides, and Mobiluncus species:
1. Consistent with normal bacterial vaginal flora.
2. Altered vaginal flora not consistent with bacterial vaginosis. This frequently represents a transitional stage. If signs or symptoms persist, repeat testing is warranted.
3. Consistent with bacterial vaginosis.
Assessment of a Gram-stained slide using the Nugent score has replaced culture as the preferred test to diagnose bacterial vaginosis.(1) While Gardnerella is the most common anaerobe found in bacterial vaginosis, other anaerobic organisms are often present along with a decrease in the amount of normal microbiota (eg, Lactobacillus species).
This system uses a 0- to 4-point scale to calculate the weighted sum of the following 3 bacterial morphotypes: Lactobacillus, Gardnerella/Bacteroides, and Mobiluncus species. A total score of greater than 6 is considered abnormal, a total score of 4 to 6 is considered a transitional stage, and a total score of 0 to 3 is considered normal. Clue cells and yeast are also reported if present.
This scored Gram stain for diagnosis of bacterial vaginosis should be used only for women in childbearing years or postmenopausal women on estrogen replacement therapy.
1. College of American Pathologists (CAP) Microbiology checklist: Bacterial Vaginosis-Evaluation of a criterion-based Gram stain is used for the microscopic diagnosis of bacterial vaginosis. CAP; 2021:35
A Gram stain with scoring of the microbial morphotypes, the Nugent scoring system, is used to evaluate the vaginal/urogenital microbiota from the Gram-stained slide. This system uses a 0- to 4-point scale to calculate the weighted sum of the following 3 bacterial morphotypes: Lactobacillus, Gardnerella/Bacteroides, and Mobiluncus species.(Chan WW: Gram stain procedure-Reporting Gram-stained vaginal smears to diagnose bacterial vaginosis and vaginitis. In: Leber AL, ed. ASM Clinical Microbiology Procedures Handbook. 4th ed. Press; 2016:3.2 [1-3])
Monday through Sunday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
87205
Test Id | Test Order Name | Order LOINC Value |
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GSBV | Gram Stain for Bacterial Vaginosis | 14361-0 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
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GSBV | Gram Stain for Bacterial Vaginosis | 14361-0 |