When is a pap test result considered abnormal?

With abnormal cells.: A pap is abnormal when there are atypical cells in it. These may be atypical from infection, in which case there would be other evidence, like white cells, organisms, blood, etc.. They can be atypical due to neoplastic changes, so there would be cells called consistent with low or high grade neoplasia. Rarely, if a cause is not pinpointed, the smear is atypical with undetermined significance.

Dysplastic cells: Pap test relies on examination of the morphology of cells in the smear. It requires considerable training to recognize abnormal cells, which are usually smaller with larger nuclei and have immature nuclei. Cells on the left are near normal and those on the right are abnormal.