The Cytomorphologic Comparison between Rehydrated Air-Dried and Conventional Wet-Fixed Pap Smears
Krit Jaiwong MD*, Kanchana Nimmanhaeminda BSc, MSc**, Sitthicha Siriaree MD*, Surapan Khunamornpong MD**
Affiliation : * Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University, Chiang Mai ** Department of Pathology, Faculty of Medicine, Chiang Mai University, Chiang Mai
Objective : To compare the cytomorphologic quality of the cervical (Pap) smears between two fixation
techniques, rehydration of air-dried smears (AD) versus wet fixation (WF).
Materials and Methods : Paired-cervical smears (AD and WF) from 172 women who underwent cervical
cytology screening at Chiang Mai University Hospital between August 2004 and September 2004 were
prospectively evaluated for the cytologic parameters and the staining qualities.
Results : The mean age of the 172 women was 41.7 years (+ 2 SD 18.1), 27 women (15.7%) were postmeno-
pausal. Absence of red blood cells in the smear background was significantly more frequent in AD smears than
in WF specimens (p = 0.0006). Air-drying artifact was more frequent in AD smears compared to those of WF
(p = 0.036) but was of only mild degree in all cases. There was no significant difference between AD and WF
smears in the cytoplasmic quality including distinctness of cell border (p = 0.30) and satisfactory staining
(p = 0.054). For the nuclear morphology, there was no significant difference between both fixation techniques
in the distinctness of nuclear border (p = 0.26) and chromatin crispness (p = 0.23) of the endocervical nuclei.
In squamous nuclei, AD smears had higher frequency of indistinct nuclear border and hazy chromatin
compared to WF smears (p = 0.003 each). However, these were observed in only mild degree and did not affect
the cytologic interpretation.
Conclusion : The quality of AD smears was slightly inferior to WF smears but was still satisfactory for cervical
cytology. AD technique may be acceptable as an alternative to wet fixation in cytologic cervical cancer
screening.
Keywords : Rehydration, Air-dried smear, Pap smear, Cervical cytology, Cytomorphologic quality
