The result of using the calretinin and BCL-2 markers for diagnosing hirschsprung disease Background: Hirshsprung disease is a congenital malformation by the absence of parasympathetic intramural ganglion cells of submucosal and myenteric plexuses in the rectum and varying lengths of bowel proximal to the rectum,resulting in a functional obstruction. Hirshsprung disease occurs in approximately 1 per 5000 live births. Rectal biopsy is the gold standard for the diagnosis.Despite the importance of using hematoxilin eosin in the diagnosis of HD, detection of ganglion cells in basic stain section can be a difficult process for the pathologist.The relatively undifferentiated and non neuronal appearance of immature ganglion cells that exist in the sub-mucosa of neonates and infants is frequently cited as a difficulty associated with hematoxilin eosin based diagnosis of HD. According, immunohistochemical and histochemical stain are used to confirm the diagnosis of HD by pathologists.2 years ago we start to use Calretinin and Bcl-2 markers for HD diagnosis at National Center for pathology in Mongolia. We don’t have research which compared hematoxylin eosin and IHC markers. Materials and methods:The study conducted using a cross-sectional model of analytical research. The Department of Pediatric Pathology of the National Center for Pathology conducts studies of rectal biopsies of 54 children who clinically suspected of Hirschsprung's disease between January 2018 and December 2019. The tissue samples stained with hematoxylin-eosin, immunohistochemical Bcl-2, calretinin markers, and the detect of nerve cells compared with the sensitivity and specificity of the test and the compatibility of the diagnosis. Results:In terms of age, 42.6% (n = 23) of infants aged 0–28 days, 38.9% (n = 21) of infants aged 29–365 days, 1.9% (n = 1) of 2 months to 2 years of age, and 7% of aged 3–5 years (n = 13), 6–12 years of age accounted for 3.6% (n = 2). 80.1% of the total surveyed children are infants and lactating children or under 1 year old. In a total of 54 children in the study, absence of ganglion cell was detected in 63% (n = 34) of hematoxylin eosin, 44.4% of calretinin markers (n = 24), and 40.7% of Bcl-2 markers (n = 22). Nerve cells were diagnosed with hematoxylin eosin staining in 37%, calretinin markers in 55.6%, and Bcl-2 markers in 59.0%. Sensitivity was determined as 91.7%, specificity as 60.0%, positive prediction rate as 64.7, negative prediction rate as 90.0, and diagnostic agreement compliance (Kappa = 0.500), (p = 0.001). Conclusions: Hirschsprung's disease diagnosed 44.7%(n-24) in rectal tissue samples. According to the result of the study, calretinin showed the highest reactivity to ganglion cells and proved to be the most specific and sensitive marker for diagnosis of Hirschsprung’s disease.