Rivaling efficacy of special stains in the identification of Barr bodies

Abstract

Background: Gender determination becomes the first priority in process of identification of a person by a forensic investigator in case of mass disaster, crime investigations, and ethnic studies. Demonstration of nuclear sex plays a vital role in determining the gender of an individual. Barr bodies (BB) are known to arise from the inactivation of the X chromosome in a female somatic cell. They are basophilic structures with varying morphology measuring approximately 0.8 × 1.1 microns in the nucleus during interphase. Various nuclear stains such as Thionine, Papanicolaou, Feulgen, Cresyl-violet, Giemsa, Aceto-orcein, and acridine orange & Routine stains can validate Barr bodies. Aim To evaluate the efficacy of Feulgen, Giemsa, and H&E stains in the demonstration of Barr bodies. Materials And Method Buccal smears were prepared from 25 males & 25 females. These smears were stained by Feulgen, Giemsa & Routine staining methods. The Barr body identification was determined by the presence of a darkly stained condensed area on nucleoplasm. The frequency of Barr body was examined by observing 100 nuclei per smear under a binocular light microscope at 100 magnification. For all BB-positive cases, Barr Body Index(BBI) was calculated and compared for the different stains used. Result Buccal cytological smears stained with Feulgen, Giemsa, and Routine stains. Samples with a presence of Barr bodies ≤2 were recorded as male and those with >2 were recorded as female under microscopic findings. The percentage of Barr bodies in Feulgen-stained slides ranged from 30.2 - 37.9 among females and 0 - 0.1 in males, Giemsa slides ranged 14.2 - 22.2 from among females and 0 - 0.3 in males, while with Routine stained slides ranges recorded were10.2 - 14.9 in females and 0 - 0.5 in males. The sensitivity of Feulgen, Giemsa, and Routine stain for detecting sex accurately was 100% and specificity was 100%, 98%, and 94% respectively. Conclusion Feulgen stain proved to be better than Giemsa and routine stain for visualizing Barr Bodies.