Comparison of Specimen Adequacy and Smear Quality in Conventional and Liquid-Based Pap Tests

Since the best method of cervical smear is a controversial subject, this study was designed to compare two methods of cervical sampling, consisting of conventional versus liquid base.

Pap smear is a screening test used to detect pre malignant and malignant processes in the endocervical canal of the female reproductive system. There are two methods, consisting of conventional Pap, in which samples are smeared directly on a microscope slide after collection, and liquid based cytology, in which the smear sample is placed in a bottle of preservative for transport to the laboratory, where it is then smeared on the slide. In this study it was decided to compare these two methods of sampling.

This randomized trial was carried out at the Amir Hospital of Semnan, Iran on 240 females undergoing Pap smear screening from April to September 2012. Patients were divided to two groups including conventional (n = 120) and liquid base cytology smear (n = 120). The results of cytological reports of both groups were compared in regards to sufficiency of sample, presence of blood in the sample, presence of infection and premalignant or malignant condition.

Specimen adequacy and smear quality were significantly better in liquid base sampling (P = 0.03); presence of benign cellular changes was not different between the two groups (P = 0.389). Diagnosis of bacterial vaginosis was significantly better with the conventional method (P = 0.007). Also, severe inflammation was more commonly reported in the conventional method than liquid base sampling test (P = 0.029).

Specimen adequacy and diagnosis of inflammatory reaction were better in liquid base smear and convention smear, respectively.