**6. Frequency of PAP smear screening**

There are different protocols advocated by different professional bodies and country policies but latest recommended by American College of Obstetricians and Gynecologists (ACOG 2012) low and average risk patients suggest that females should start screening using PAP smear from the age of 21 years and repeating every three years until 29. From the age of 30 years PAP smear alone every three years smear screening alone every 3years with termination of screening at the age of 65 years if still negative. High-risk patients such as off springs of mothers exposed to diethylstilbestrol, immunosuppressed patients, and patients with CIN2 or higher who had been treated are however advised against following the routine screening guidelines for low risk patients.

Patients who had had hysterectomy and had never had any CIN2 or greater can have discon‐ tinuation of screening using the Pap smear or HPV testing.

#### **6.1. Liquid based cytology**

This method is an innovation to improve the sensitivity of the conventional pap smear where samples are suspended in liquid media, centrifuged to concentrate the exfoliated cells which are subjected thereafter to cytology. The Food and Drug Adminstratio in the USA approved Thinprep and BD Surepath in the years 1996/1999 for the purpose of analyzing cytology samples.

The superiority of this screening method is based on improved cell collection and the random distribution of cells collected which is more representative. This method reduced the propor‐ tion of unsatisfactory smears in a study by(Ronco et al, 2007, Arbyn et al 2008) but did not show improved sensitivity instead has a low predictive value to detect CIN 2 and above relative to the traditional Pap smear. A cost analysis also revealed increased cost relative to Pap smear (De Jager et al 2013).
