What are the possible cervical smear abnormalities?

In France, cytology testing laboratories should apply the Bethesda system (TBS), which standardises the classification of cervical smear abnormalities and thereby permits a common language and clinical approach to the issue.

In 95% of cases, cervical smear results are normal:

this means that no abnormalities have been seen in the cells that could raise a high risk possibility of cervical cancer, notwithstanding, the smear could indicate a vaginal infection (such as for example a fungal infection), which is not in itself associated with any carcinogenic risk and simply requires appropriate disinfection.

In 4-5% of cases abnormalities can appear and include the following:

  • Smear with atypical Squamous Cells of Undetermined Significance (ASC-US) which account for 1-2% of total smear test results. This means that the cytologist has identified mild cellular abnormalities with no immediate cervical cancer risk but require further monitoring and possible treatment. In this case the clinician has three possible courses of action:
    • refer the patient for repeat smear tests 6 months and 12 months after the initial observation,
    • refer the patient for a colposcopy examination (using a microscope to examine the cervix closely)
    • request an HPV (Human Papillomavirus Virus) test: this checks the intial smear test for high risk strains of the virus. When these are absent one is reassured (the absence of a potentially oncogenic virus vastly reduces the probability of cervical precancerous lesions). However if high risk strains of the virus are present then a colposcopy is required to detect any potential cervical lesions.
  • Smear type ASC-H, atypical squamous cells not excluding the possibility of high-grade intraepithelial lesions which account for less than 0.5% of total smear test results. In this situation the cytologist has detected cell abnormalities that require further research in order to be sure of their identity.  The clinician will in this case always:
    • Refer the patient for a colposcopy
  • Smear test results suggesting the presence of a low grade lesion which account for 1-2% of total smear test results. In this situation the cytologist detects low grade cell abnormalities suggesting either an HPV (Human Papillomavirus) infection or mild dysplasia (CIN 1, Cervical Intraepithelial Neoplasia grade 1). With this case the clinician may:
    • Refer the patient for a colposcopy in order to examine the cervix further and either confirm the presence of a lesion or perform one or several biopsies.
    • Perform a further cytology examination (another smear test) after 6 months and again after 12 months. This is because low grade cervical lesions can and do revert back without any treatment. However should there be continued evidence of low grade lesions during the control smears, the clinician will strongly advise a colposcopy.
  • Smear test results suggesting the presence of a high grade lesion which account for less than 1% of total smear test results. In this situation the cytologist detects high grade cell abnormalities suggesting moderate or severe dysplasia (CIN 2 or 3, Cervical Intraepithelial Neoplasia grade 2 or 3). These types of lesions have a high probability of being precancerous. With this case the clinician:
    • Refers the patient for a colposcopy


  • Smear test results suggesting the presence of a glandular lesion. AGC Atypical Glandular Cells, ACIS Adenocarcinoma in situ) which account for less than 0.1% of total smear test results. The cytologist detects cell abnormalities in the cervix. This situation is very rare since the occurrence of these lesions is less frequent whilst being more difficult to detect as they are situated right at the neck of the womb which is difficult to access visually. With this situation the clinician’s course of action requires:
    • Referral of the patient for a colposcopy,
    • Performance of  an endocervical curettage
    • Request for an HPV (Human Papillomavirus) test
    • Examination of the uterus for the presence of abnormal cells originating not from the cervix but potentially from the endometrium, the fallopian tubes, or the ovaries via a pelvic scan and/or an endometrial biopsy.


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