American Journal of Infectious Diseases 8 (1): 1-4, 2012 ISSN 1553-6203 © 2012 Science Publications Corresponding Authors: Behzad Mohsenpour, Department of Infectious Disease, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran Tel: +989123502771 Fax: +988713285990 1 Comparing of Routine 2 Mercaptoethanol (2ME) and Coombs Wright Plus 2ME Katayoun Haji Bagheri, Behzad Mohsenpour and Shahla Afrasiabian Department of Infectious Disease, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran Abstract: Problem statement: Serologic tests like Wright, Wright containing Anti-human globulin (Coombs Wright) and 2ME are the main methods of diagnosing brucellosis. The routine method of using Wright test and then performing 2ME is not enough sensitive to diagnose brucellosis. The goal of this study is to compare the results of routine 2ME with 2ME on serum containing antihuman globulin (Coombs Wright+2ME). Approach: In this study 100 patients with brucellosis were evaluated. The serums of these patients were tested using routine 2ME and Coombs Wright with adding 2ME. Then the results of these tests were compared. Sensitivity and Specificity of these two methods were also calculated. Results: The sensitivity of routine 2ME was 52%. The sensitivity of 2ME Plus Coombs Wright was calculated as 97%. Sensitivity and Specificity of routine 2ME method against Coombs Wright plus 2ME method were respectively 53% (54-51: CI) and 75% (95-31: CI). Conclusion: According to the results, Coombs Wright plus 2ME can be used for negative 2ME test patients in order to follow up their response to treatment. In addition, it is not necessary to do Wright test and routine 2ME and instead of them, Coombs Wright plus 2ME can be used. Key words: Brucellosis, wright test, coombs test, 2-Mercaptoethanol (2ME), susceptible patients INTRODUCTION Brucellosis is one of zoonoses which are still highly prevalent in Iran (Hatami et al., 2010; Roushan et al., 2004; Pappas et al., 2005; Moradi et al., 2006). According to WHO report, the number of diagnosed and reported patients may be 10 to 25 times fewer than real number of infected people in the society; one of the main reasons may be the difficulty of diagnosing the disease and especially chronic brucellosis (Wise, 1980; Roth et al., 2003). The only precise method of diagnosis is culture of brucella Spp; however the sensitivity of the culture is related to accuracy of the laboratory and other conditions. The results of positive culture vary from 15- 90% (Wise, 1980; Gotuzzo et al., 1986; Yagupsky, 1999; Memish et al., 2000; Roushan et al., 2004; Pappas et al., 2005) and of course it is not always possible to culture blood. Recently, PCR methods are developed but they are not accepted as the routine method, hence serologic tests like Wright and Coombs Wright are the most practical methods (Young, 1991; Serra and Vinas, 2004; Yu and Nielsen, 2010). Sensitivity and specificity of Wright test are different (Serra and Vinas, 2004; Surucuoglu et al., 2009; Yu and Nielsen, 2010). As sometimes their result is false negative (Bettelheim et al., 1983; Surucuoglu et al., 2009), negative Wright test can not reject the probability of brucellosis in endemic regions (Serra and Vinas, 2004). After a positive Wright, 2-Mercaptoethanol (2ME) is used as a complementary test in order to distinct Active brucellosis from non active brucellosis and to detect previous contacts with brucellosis Antigen and for follow up of treatment. However in patients with negative Wright test we cannot perform 2ME test. In such situation Coombs test that contains anti-human globulin is suitable (Coombs Wright plus 2ME), as it reduces the number of false negative results (Bettelheim et al., 1983; Dahouk et al., 2003; Mohsenpour et al., 2011). Therefore, it seems using 2ME test together with Coombs test can be more accurate in confirming active chronic brucellosis than 2ME with Wright test. Nevertheless, the sensitivity and specificity of this test in people with positive Coombs test are unknown and there is no study regarding this subject. Because of high prevalence of brucellosis in Iran and the importance of quick diagnosis and treatment of this disease and in order to follow up treatment responses, it is necessary to develop an especial, sensitive and accessible laboratory method (Serra and