How reliable is cervical screening?

A smear test does not diagnosis cervical cancer.  However, smear tests can detect early changes in the cells of your cervix. But like all screening tests, they are not perfect or completely accurate. There is always a small chance that abnormal cells may not show up. This may happen for a number of reasons:

  • The brush may not pick up the cells from your cervix.
  • The abnormal cells may be hidden from view by blood or mucus.
  • The abnormal cells may look very much like normal cells.
  • There may be very few abnormal cells in the sample. This can happen in older women or depend on the time of your period.
  • Sometimes it is harder to spot abnormal cells in the laboratory.

Occasionally, the test may need to be done again if the cervical cells are hidden by blood or mucus, if there is infection or inflammation, or if there are not enough cells. Because early changes may not show up, you must continue to go for regular smear tests.


Irish Cancer Society Logo221+ Patient Support Group thanks the Irish Cancer Society for permission to use the text of their booklet Cervical Cancer, What You Should Know
and acknowledges the contribution of the original authors of the booklet.