How is a liquid-based cytology (LBC) Pap smear performed?

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Last updated: October 8, 2026 • View editorial policy

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How to Perform a Liquid-Based Cytology (LBC) Pap Smear

For liquid-based cytology, collect cervical cells using either a cervical broom device OR the combination of an extended-tip spatula plus endocervical brush, then immediately rinse the sampling device(s) thoroughly in a vial containing liquid preservative fixative and label the container with the patient's name. 1

Patient Preparation

Before the procedure, instruct the patient to:

  • Avoid douching for 48 hours prior to testing
  • Refrain from intercourse for 48 hours before the test
  • Do not use tampons, birth control foams, jellies, vaginal creams, or vaginal medications for 48 hours prior 1
  • Schedule to avoid heavy menstrual flow when possible, though do not defer if abnormal bleeding is present (intermenstrual, postcoital, or postmenopausal bleeding) 1

Collection Methods

Option 1: Cervical Broom Device (Preferred for Pregnant Women)

This is the recommended single-device method for LBC, particularly in pregnancy 1:

  1. Insert the long central bristles of the broom into the endocervical os
  2. Press the broom against the cervix so the outer bristles bend against the ectocervix
  3. Rotate in ONE direction only for 5 complete rotations (do not reverse direction, as this causes cell loss) 1
  4. Immediately rinse the broom as thoroughly as possible in the preservative vial, OR snap off the handle and leave the broom head in the fixative (follow manufacturer-specific instructions) 1

Option 2: Extended-Tip Spatula Plus Endocervical Brush

Use a plastic extended-tip spatula (required for LBC systems) 1:

  1. Sample the ectocervix and transformation zone with the extended-tip spatula
  2. Sample the endocervical canal with the endocervical brush
  3. Rinse both devices carefully and thoroughly in a single vial containing the preservative fixative 1
  4. Some manufacturers recommend separating or cutting the sampling devices from their handles and placing them directly into the fixative 1

Critical Technical Points

  • Only plastic sampling devices should be used for LBC 1
  • Cotton swabs are NOT appropriate for LBC collection 1, 2
  • The sampling device must be placed directly into liquid fixative to provide immediate fixation, which eliminates air-drying artifact 1
  • Label the vial with the patient's name before sending to the laboratory 1

Key Advantages of LBC Over Conventional Pap Smears

The evidence strongly supports LBC's superiority:

  • Reduces unsatisfactory specimens significantly (1.33% vs 7.33% for conventional) 3, 4
  • Improves detection of high-grade lesions (CIN2+) with sensitivity of 100% vs 75% for conventional smears 4
  • Better sample adequacy with more uniform cell distribution and reduced obscuring factors like blood and inflammation 1
  • Allows residual material for ancillary HPV DNA testing 1
  • Higher detection rate for histology-confirmed abnormalities (35% increase) and CIN2+ lesions (27% increase) 5

Common Pitfalls to Avoid

  • Do not rotate the cervical broom back and forth - this causes cell loss; rotate in one direction only 1
  • Do not use cotton swabs for endocervical sampling with LBC systems 1
  • Do not use wooden spatulas - only plastic devices are appropriate for liquid-based systems 1
  • Do not delay fixation - immediate placement in preservative is essential to prevent air-drying artifact 1

References

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.