Best fixative for Pap smear:: (A) 95% ethanol + 5% ether, (B) 10% formaldehyde, (C) 80% isopropyl alcohol, (D) 90% ether + alcohol
Answer is A. ANS. AFixatives:* Pap smear: 95% ethanol + 5% ether* Light microscopy: 10% formaldehyde* Electric microscopy: 2% glutaraldehyde* For liquid-based cytology: Methanol* For bone marrow biopsy: Zenker's fluid* For bone marrow aspirate: Helly's fluid* Cell block: Bouin's fluid* Karyotyping fixatives: Carnoy's fixative (3:1 methanol to glacial acetic acid)* Gastrointestinal biopsies: Bouin's fluid.