Specimen Sources

This section will cover the critical aspects of specimen collection for the diagnosis of infections within the female and male genital tracts. Proper collection is paramount for accurate results and patient care

Female Specimens

Vaginal Specimens

• Purpose: Primarily used to diagnose vaginitis, including bacterial vaginosis (BV), candidiasis (yeast infections), and trichomoniasis
• Collection Methods
  • Vaginal Swab: A sterile swab is gently inserted into the vagina, rotated to collect secretions, and then removed
  • Speculum-Aided Collection: A speculum is used to visualize the vaginal walls, and a swab is used to collect secretions directly from the vaginal walls. This is particularly useful for obtaining a good sample and for assessing the presence of discharge
• Specific Considerations
  • Timing: Ideally, collect specimens before any douching or topical medications are used
  • Sample Site: Swab the vaginal walls, focusing on areas with visible discharge
  • Transport: Transport swabs in appropriate transport media (e.g., Amies, Stuart’s) to maintain organism viability. For certain organisms (e.g., Trichomonas vaginalis), the specimen should be processed quickly or placed in specific transport media
  • Self-Collected Samples: Some tests (e.g., for HPV or certain STIs) may utilize self-collected vaginal swabs. These must be performed following specific instructions to ensure accurate results

Cervical Specimens

• Purpose: Crucial for diagnosing cervicitis and identifying sexually transmitted infections (STIs) such as Neisseria gonorrhoeae and Chlamydia trachomatis
• Collection Methods
  • Endocervical Swab: A speculum is inserted to visualize the cervix. Using a sterile swab, the endocervical canal is accessed, and the swab is rotated to collect secretions. The swab should be inserted gently to avoid causing bleeding
  • Cytobrush (for certain tests): A cytobrush may be used to collect a more robust sample, especially for cytology or for molecular testing
• Specific Considerations
  • Patient Positioning: The patient should be in the lithotomy position for optimal access
  • Visualization: Ensure the cervix is adequately visualized with the speculum
  • Sample Site: Rotate the swab within the endocervical canal to maximize specimen collection
  • Blood Contamination: Avoid excessive bleeding, as blood can interfere with some tests
  • Transport: Transport swabs in appropriate transport media. For N. gonorrhoeae, consider using a special transport medium designed to preserve the bacteria. For C. trachomatis, the swab is often placed in a specific transport medium

Endocervical Specimens

• Purpose: Identical to cervical specimens. The term “endocervical” emphasizes the specific location of the sample collection within the cervical canal
• Collection Methods: Same as Cervical Specimens (see above)

Male Specimens

Urethral Specimens

• Purpose: Primarily used to diagnose urethritis and identify STIs such as Neisseria gonorrhoeae and Chlamydia trachomatis
• Collection Methods
  • Urethral Swab: The patient should not have urinated for at least one hour before collection. A small sterile swab is gently inserted into the urethra (approximately 2-4 cm), rotated to collect secretions, and then removed
  • First-Catch Urine: First-catch urine (initial stream) can be used to detect urethral infections. The patient collects the first part of the urine stream into a sterile container. This method is less invasive than a urethral swab and is often preferred for screening
• Specific Considerations
  • Patient Comfort: Explain the procedure to the patient to minimize anxiety
  • Urethral Access: Gently insert the swab, avoiding excessive force
  • Sample Site: Rotate the swab to collect secretions
  • Transport: Transport swabs in appropriate transport media. For N. gonorrhoeae, consider using a special transport medium. For C. trachomatis, the swab is often placed in a specific transport medium

Prostatic Fluid

• Purpose: Used to diagnose prostatitis (inflammation of the prostate gland)
• Collection Methods
  • Prostatic Massage: The prostate is massaged rectally by a physician to express fluid into the urethra. A urine sample (midstream) is collected after the massage to analyze the expressed prostatic secretions
• Specific Considerations
  • Medical Procedure: This is a medical procedure performed by a qualified healthcare provider
  • Patient Preparation: The patient may need to abstain from sexual activity prior to the procedure
  • Specimen Collection: The urine sample should be collected midstream after the prostatic massage
  • Transport: Process the urine sample promptly

Other

• Semen: Semen samples may be collected for culture when there is a suspicion of epididymitis or other infections. The collection procedure involves masturbation into a sterile container

General Considerations

• Patient Education: Provide clear instructions to the patient regarding the collection procedure, including any necessary preparation (e.g., not urinating beforehand)
• Aseptic Technique: Maintain strict aseptic technique throughout the collection process
• Proper Labeling: Label all specimens with the patient’s name, date of birth, and the specific anatomical site from which the sample was collected
• Transport Time and Conditions: Transport specimens to the laboratory promptly. Follow the laboratory’s specific guidelines for transport media and temperature requirements to ensure organism viability
• Quality Control: Ensure that all collection materials are sterile and that the collection process is performed correctly
• Safety Precautions: Always wear appropriate personal protective equipment (PPE), including gloves, and follow standard precautions when handling specimens

Key Terms

• Vaginitis: Inflammation of the vagina, often caused by infection. Common causes include bacterial vaginosis, candidiasis (yeast infection), and trichomoniasis
• Cervicitis: Inflammation of the cervix (the lower, narrow end of the uterus that opens into the vagina). Can be caused by various infections, including sexually transmitted infections (STIs)
• Urethritis: Inflammation of the urethra (the tube that carries urine from the bladder). Often caused by STIs
• Sexually Transmitted Infections (STIs): Infections transmitted through sexual contact. Examples include Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, and others
• Bacterial Vaginosis (BV): A common vaginal infection caused by an imbalance of the normal bacteria in the vagina. Not typically considered an STI, but can be associated with sexual activity
• Endocervix: The inner lining of the cervix, where specimens are often collected to test for infections
• First-Catch Urine: The initial portion of the urine stream, often collected for testing for urethral infections in males
• Prostatitis: Inflammation of the prostate gland, which can be caused by bacterial infections
• Speculum: A medical instrument used to open the vagina or other body cavity to allow for visualization and access for procedures
• Culture: A laboratory procedure used to grow microorganisms (like bacteria or fungi) in a controlled environment to identify them. Used to diagnose infections