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. 2023 Dec 28;25(1):449. doi: 10.3390/ijms25010449

Table 1.

Methods for BV diagnosis.

Method Main Criteria Advantages Disadvantages Characteristics
Clinical methods
Amsel’s criteria [5] “Wet mount” microscopy

  1. Abnormal vaginal discharge with «fishy» odor;

  2. Vaginal pH > 4.5;

  3. Positive whiff test when vaginal fluid is exposed to 10% potassium hydroxide;

  4. “Clue” cells on wet mount.

 Onsite diagnostic; symptomatic BV is diagnosed clinically when ≥3 of 4 clinical signs are present Time-consuming;
Biased;
Abnormal vaginal discharge is present only in 50% of BV-affected women;
Absence of pH strips;
Absence of potassium hydroxide;
Healthcare providers do not distinguish “clue” cells and “pseudo-clue” cells. 		Sensitivity: 37–70%,
Specificity: 94–99% when compared to Nugent’s method
Nugent’s system [6] Microscopic method based on gram-stained smears is calculated by assessing the presence of large Gram-positive rods (Lactobacillus morphotypes; scored as 0 to 4), small Gram-variable rods (Gardnerella vaginalis morphotypes; scored as 0 to 4), and curved Gram-variable rods (Mobiluncus spp. morphotypes; scored as 0 to 2):
0–3—BV negative
4–6—intermediate
7–10—BV positive		 Unbiased, cost-effective, simple to perform, 7 + is considered indicative of BV Does not involve “clue” cells;
Delayed result transmission;
Time-consuming;
“Intermediate” result (4–6) is hard to interpret (possibly vaginal candidiasis, aerobic vaginitis, etc.);
Determination of only certain bacterial morphotypes, approximate conclusion on vaginal biotope composition.
“Clue” cells are not determined		 Sensitivity: 89%,
Specificity: 83% when compared to Amsel’s criteria
Hay-Ison’s criteria [7] Microscopic method based on gram-stained smears and assessing bacterial morphotypes:
0—no bacteria
1—absent BV signs
2—no obvious BV signs
3—BV signs
4—Gram-positive cocci		 Unbiased, simple to perform Delayed result transmission;
Does not involve “clue” cells;
Time-consuming;
“Intermediate” result is hard to interpret;
Lactobacillus morphotypes are not determined;
Determination of only certain bacterial morphotypes, approximate conclusion on vaginal biotope composition.		 Sensitivity: 98%,
Specificity: 96% when compared to Amsel’s criteria.
Positive predictive value: 94%
Negative predictive value: 96%
Savicheva’s criteria [8] Microscopic investigation of vaginal smears for BV signs:

  1. Leukocytes/epithelial cells ratio less than 1:1;

  2. “Clue” cells;

  3. Bacterial morphotype of lactobacilli is low or absent;

  4. Other microorganisms are present.

  1. Unbiased;

  2. Cells composition determination: “clue” and “pseudo-clue” cells, morthotypes of lactobacilli, basal/parabasal epithelial cells;

  3. Inflammatory response evaluation: leukocytes/epithelial cells ratio;

  4. Ratio of lactobacilli and other bacteria (dominant, low or absent);

  5. Time-effective.

 Assessment of bacterial morphotypes. Sensitivity: 98%,
Specificity: 96% when compared to Amsel’s criteria.
Molecular methods
Fluorescence in situ hybridization (FISH) [9] Fluorescent microscopy using 16S rRNA stained probes In-situ biofilm/In-situ dysbiosis detection Cost-consuming;
Expensive equipment;
Manual test;
Selection of specific primers;
Needs wider implementation to the practice.		 Sensitivity: 84.6%,
Specificity: 97.6–100% when compared to Nugent’s method
Next generation sequencing (NGS) [10,11] 16S rRNA gene sequencing A quantitative assessment of vaginal microbiome Cost-consuming;
Expensive equipment.
Results need to be interpreted correctly.		 Sensitivity: 95% when compared to clinical methods
Multiplex PCR [3,12] Quantitative multiplex PCR for BV diagnosis Commercial automated tests, easy to perform, automated result acquisition. Cost-consuming;
Limited data;
No comparison between biofilm detection (FISH) and quantitative PCR.		 Sensitivity: 91–97%,
Specificity: 77–91% when compared to clinical methods