What is the proper procedure for collecting chlamydia and gonorrhea PCR samples from urine, rectal, and throat swabs?

Proper Collection Procedures for Chlamydia and Gonorrhea PCR Samples

For optimal detection of chlamydia and gonorrhea, patients should not have urinated for at least 2 hours prior to specimen collection, and specific collection techniques must be followed for each anatomical site. 1

Urine Specimen Collection

• First-catch urine is the preferred method for male patients and an acceptable alternative for females
  • Patient should not have urinated for at least 2 hours before collection
  • Collect only the initial 15-30 ml of the urine stream
  • First 4-5 ml contains the highest concentration of organisms 1
  • Place in appropriate transport container specified by the test manufacturer

Endocervical Specimen Collection

1. Collect specimens after obtaining any gram-stained smear, gonorrhea culture, or Pap smear
2. Use a sponge or large swab to remove all secretions and discharge from the cervical os
3. Use the swab supplied or specified by the test manufacturer
4. Insert the swab 1-2 cm into the endocervical canal (past the squamocolumnar junction)
5. Rotate the swab against the wall of the canal for 10-30 seconds
6. Withdraw without touching vaginal surfaces
7. Place in appropriate transport medium 2

Urethral Specimen Collection

1. Ensure patient has not urinated for at least 2 hours
2. Collect after obtaining any gram-stained smear or gonorrhea culture
3. Use the manufacturer-specified swab
4. Gently insert the swab into the urethra (females: 1-2 cm, males: 2-4 cm)
5. Rotate the swab in one direction for at least one revolution for 5 seconds
6. Withdraw and place in appropriate transport medium 2

Rectal Specimen Collection

• Insert the swab 2-3 cm into the rectum
• Apply lateral pressure to sample the rectal crypts
• Rotate the swab for 5-10 seconds
• Withdraw and place in appropriate transport medium
• Self-collection is a valid alternative with comparable sensitivity to clinician collection 3

Pharyngeal (Throat) Specimen Collection

• Swab the posterior pharynx and tonsillar pillars
• Avoid touching the tongue, uvula, or other oral surfaces
• Place in appropriate transport medium
• Self-collection is acceptable with proper instruction

Important Considerations

1. Test Selection: Nucleic acid amplification tests (NAATs) are the gold standard with superior sensitivity (84-92%) and specificity (>97%) compared to culture methods 1

2. Specimen Preferences:

   • For women: Vaginal swabs are the recommended specimen of choice with highest sensitivity (92%) and specificity (98%) 4
   • For men: First-catch urine is recommended with high sensitivity (88%) and specificity (99%) 1

3. Quality Assurance:

   • Without proper collection, >10% of specimens may be unsatisfactory 2
   • Periodic cytologic evaluation of specimen quality is recommended

4. Transport Conditions:

   • Follow manufacturer's instructions for transport medium and conditions
   • Some specimens can be stored at room temperature for several days 5

5. Common Pitfalls to Avoid:

   • Using wooden-shaft swabs (may contain substances toxic to organisms)
   • Collecting specimens after antibiotic use
   • Improper labeling of multiple site specimens
   • Failure to collect from all potentially infected sites
   • Touching unintended surfaces during collection

By following these standardized collection procedures, you can maximize the detection of chlamydia and gonorrhea infections, leading to appropriate treatment and prevention of complications such as pelvic inflammatory disease, chronic pelvic pain, and infertility 1.