Rehydrated air-dried Pap smears as an alternative to wet-fixed smears.

Objective: To assess the effect of rehydration on air-dried Pap smears and to compare them with conventional, wet-fixed smears.

Study Design: Paired cervical smears were obtained from 419 women. One set was labelled "Routine" (fixed immediately in 95% ethanol) and the other, "Rehydrated" (air-dried, rehydrated and then fixed). The latter were further subdivided into groups A-F depending on the duration of air drying. The staining quality of the smears was assessed, after adequate blinding to remove bias, and graded. The chi 2 test was performed to compare parameters in the two sets of smears.

Results: Of the 397 pairs found to have adequate cellularity, 6% of the Routine group and 4% of the Rehydrated were "unsatisfactory due to poor fixation." Smears rehydrated within two hours of air drying as well as those refrigerated within two hours and rehydrated after 48 hours produced a staining quality as good as that of the conventional, wet-fixed smears. Rehydration caused lysis of red blood cells in the background.

Conclusion: Rehydration of air-dried Pap smears within two hours of preparation produces staining quality equal or superior to that of conventional, wet fixed ones. It has the added advantage of being less cumbersome for the clinical personnel involved in smear making.