Commercial laboratory practice evaluation of air-dried/rehydrated cervicovaginal smears vs. traditionally-fixed smears

Rehydration of Air-Dried Smears with Normal Saline: An Alternative for Conventional Wet Fixation Method in Cervical Cytological Study

Context:

Papanicolaou (Pap) smear is an effective exfoliative cytological investigation done for early recognition of cervical cancer. It also plays role in diagnosis of inflammatory lesions of cervix.

Aims:

The aim of this study is (1) to compare the cytomorphological features in conventional Pap smear (C-PAPS) and rehydrated air-dried Pap smear (RADPS) and (2) to evaluate the efficacy of RADPS in cytodiagnosis of cervical lesion by comparing with cytomorphological features of conventional wet-fixed Pap smear.

Subjects and Methods:

Paired cervical smears were prepared for 247 patients. One was labeled as C-PAPS and another was labeled as RADPS. Comparison of both smears was done for various cytomorphological parameters.

Results:

Out of 247 smears, 2.4% RADPS and 7.3% C-PAPS were reported as unsatisfactory. Red blood cell (RBC) background was present in 2% of RADPS and 42% of C-PAPS. Cytolysis and air-drying artifact were observed more in C-PAPS amounting to 2% and 4% in RADPS and 11% and 15% in C-PAPS. Cytoplasmic staining (97% RADPS vs. 94% C-PAPS) was superior in RADPS. Cell border, nuclear border, and chromatin of squamous and endocervical cells were better appreciated on RADPS compared to C-PAPS, and also statistically significant difference was observed.

Conclusion:

Rehydrated air-dried technique can be satisfactory alternative for conventional wet fixation method which can be followed routinely or in conjugation with C-PAPS, especially in cervical screening programs.

Rehydration of Air-Dried Smears versus Wet Fixation: A Cross-Sectional Study

BACKGROUND

The Papanicolaou (Pap) smear is an effective method for early detection of cervical cancer. The routine practice of staining is to immediately fix the cervical smear in 95% ethyl alcohol. An alternative method of rehydrating the air-dried cervical smears followed by fixation and conventional staining method can overcome most of the problems associated with short supply and storage of alcohol, wet fixing of slides and transporting them to the cytology centre if the Pap smears are prepared at a peripheral centre. There are only few studies regarding rehydration of cervical smears as a substitute for wet fixation.

AIM

The current study was undertaken to assess this technique as an alternative method for conventional wet-fixed smears.

MATERIAL AND METHODS

This study was done over a period of 15 months in a tertiary care setup. Two sets of 461 cervical smears were examined; the smears in the first set were fixed in 95% ethyl alcohol and the other set of 461 smears was air dried, rehydrated and then fixed in 95% ethyl alcohol. Both the smears were stained with Pap stain, examined for preservation of cytomorphological features and evaluated using the modification of parameters given by Ng et al. [Acta Cytologica 1994;38:56-64].

RESULTS AND ANALYSIS

Two sets of 461 smears each, one air dried and rehydrated and the other wet fixed in alcohol, were evaluated for cytomorphological preservation, and comparison was done. In wet-fixed smears, morphology was excellent in the majority of cases (80.7%). Cytomorphology was optimal in 18% and suboptimal in 1.3% of the cases. The air-dried and rehydrated smears showed excellent morphological preservation in 67%, followed by 29.9% optimal and 2.8% suboptimal preservation. The p value was >0.05, which was not significant.

CONCLUSION

Rehydration, followed by fixation of air-dried smears, is a simple, feasible, applicable and reliable fixation technique which is comparable to the wet-fixed conventional technique used for cervical smears and can be applied for evaluation on a routine basis.