How is a vaginal swab collected for Sexually Transmitted Infections (STIs) testing?

How to Properly Collect a Vaginal Swab for STI Testing

For STI testing, self-collected vaginal swabs are the preferred specimen collection method due to their high sensitivity, acceptability to patients, and ease of collection.

Collection Procedure for Vaginal Swab

Preparation

• Clean the vaginal introitus (opening) using a sterile gauze swab 1
• Use a cotton-wool or Dacron swab on an aluminum shaft for collection 1

Collection Steps

• Insert the vaginal speculum, which may be moistened with warm water (if provider-collected) 1
• For self-collection or provider collection without speculum:
  • Insert the swab carefully through the hymen into the vagina 1
  • Collect material from the back wall of the vagina 1
  • Use circular motions for 10 seconds to ensure adequate sampling 1

After Collection

• Place the swab directly into the appropriate transport medium as specified by the laboratory 1
• Transport within the timeframe recommended for the specific test being performed 1

Advantages of Vaginal Swabs for STI Testing

• Vaginal swabs have superior sensitivity (86%) compared to other specimen types for detecting multiple STIs 2
• Self-collected vaginal swabs are almost as accurate as physician-collected samples with 91% sensitivity and 99% specificity 3
• First-void urine samples have lower sensitivity (63%) and should be avoided when possible 2

Patient Acceptability

• Studies show that 99% of women report self-collection of vaginal swabs is easy to perform 4
• 84% of women prefer self-collection to a traditional gynecological examination 4
• 97% of women state they would undergo testing more frequently if self-testing were available 4
• Self-collection dramatically increases STI detection rates when pelvic exams are not performed 5

Types of STIs Detectable by Vaginal Swab

• Vaginal swabs can effectively detect:
  • Chlamydia trachomatis 1, 2
  • Neisseria gonorrhoeae 1, 2
  • Trichomonas vaginalis 1, 2
  • Mycoplasma genitalium 2
  • Human papillomavirus 2
  • Bacterial vaginosis 1
  • Yeast infections 1

Testing Technology

• Nucleic Acid Amplification Tests (NAATs) are the preferred testing method for vaginal swabs 1
• Many NAATs are FDA-approved for testing patient-collected vaginal swabs in clinical settings 1
• The same specimen collection device is often used for multiple STI tests simultaneously 1

Common Pitfalls and How to Avoid Them

• Insufficient sampling: Ensure the swab makes contact with the vaginal walls for adequate time 1
• Contamination: Clean the introitus before collection to avoid external contamination 1
• Improper storage: Follow laboratory-specific transport media and timeframe requirements 1
• Inadequate patient instruction: Provide clear instructions for self-collection to ensure proper technique 6