Results: Carb-3conc with an in-house optimized protocol gave the highest H-scores in classical Hodgkin lymphoma, renal tumours and normal kidneys. Carb-3RTU and MMAconc gave slightly lower scores, while MMARTU and BY87conc gave the lowest scores and a large proportion of false negative reactions. All in-house optimized protocols gave better staining results than vendor protocols. Conclusion: The importance of antibody selection and protocol optimization in immunohistochemical laboratories is emphasized. Objective: Studies show that there is association between stress and pathophysiological changes in reproductive system. The main aim of this study was to determine the pathological effects of immobilization stress on testes tissue and serum testosterone level in male rats. Method: Wistar rats were randomly divided into control, acutely or chronically immobilized groups of 10 in each. Animals were immobilized for 2 h/day or 8 h/day for a period of 3 weeks or 1 week in chronically or acutely immobilized groups, respectively. After 6 weeks, blood samples were collected using cardiac puncture method. Following serum collection, testosterone level was measured by radioimmunoassay method. The effect of immobilization stress on testes histology was also examined. Data were statistically analyzed and compared between groups using ANOVA.