Cervicovaginal Swab: What It Can and Cannot Do

In gynecology, the cervicovaginal swab (CVS) is a common diagnostic tool. Often prescribed in cases of unusual vaginal discharge, recurrent infections, or as part of a fertility assessment, it plays an important role in evaluating the vaginal flora and detecting certain infections. But what exactly does this test involve, and what are its limitations.

What is a CVS?

A CVS involves collecting cells and secretions from the cervix and/or vagina using a sterile swab. The sample is then sent to the laboratory for microbiological analysis. Depending on the doctor’s request, the lab may conduct:

• A direct microscopic examination,

• A bacterial culture,

• A fungal culture,

• Sometimes even molecular tests (PCR).

  
  

What Can It Detect?

A standard cervicovaginal swab can detect:

1. Bacterial Vaginosis (overgrowth of anaerobic bacteria, imbalance of flora)

2. Candidiasis (yeast infections)

3. Trichomoniasis (caused by the parasite Trichomonas vaginalis)

4. Some sexually transmitted infections like gonorrhea (if specifically requested)

5. Group B Streptococcus (especially in pregnancy)

It is also useful for evaluating vaginal flora (presence of protective Lactobacillus) or confirming recurrent infections.

What It Cannot Do

However, the CVS has limitations:

• It does not systematically detect all STIs, especially Chlamydia trachomatis or Mycoplasma, which require molecular tests like PCR.

• It does not assess fertility directly (e.g., it doesn’t provide information about ovulation or fallopian tube patency).

• A “normal” result does not rule out infections located higher in the genital tract (e.g., pelvic inflammatory disease).

• It cannot replace a Pap smear (which screens for cervical cell abnormalities or HPV).

  
  

Conclusion

The CVS is a valuable tool when used appropriately. However, it must be interpreted in the clinical context and is often only one part of a broader diagnostic approach. Always discuss the results and their meaning with your healthcare provider. In case of symptoms or doubt, do not hesitate to request a more comprehensive assessment, including molecular testing if necessary.

Dr. Sandra Yene Amougui