The increase in TB case detection using ICC observed in this study may be attributed to the ability of ICC to detect fragments of antigen rather than the presence of the intact bacilli which is a prerequisite for ZN staining [30],[31]. and 25 TB lymphadenitis) and 67 non-TB settings. Each specimen was subjected to Ziehl-Neelsen (ZN) staining, tradition on Lowenstein Jensen (LJ) medium, cytological exam, Polymerase Chain Reaction (PCR) using Is definitely1081gene sequence like a primer and immunocytochemistry (ICC) with polyclonal anti-MPT64 antibody. All individuals were screened for HIV. == Result == ICC was positive in 38 of 51 instances and in the 7 of 67 settings giving an overall level of sensitivity and specificity of 74.5% and 89.5%, respectively. Using Is definitely1081-PCR like a research method, the sensitivity and specificity, positive and negative predictive value of ICC was 88.1%, 89.5%, 82.2% and 93.2%, respectively. The case detection rate improved from 13.7% by ZN stain to 19.6% by LJ culture, to 66.7% by cytology and 74.5% by ICC. == Summary == Immunocytochemistry with anti-MPT64 antigen improved detection of TB in pleural effusion and lymph node aspirates. Further studies using monoclonal antibodies on samples from additional sites of EPTB is recommended to validate this relatively simple diagnostic method for EPTB. == Mouse monoclonal to GLP Electronic supplementary material == The online version of this article (doi:10.1186/s12879-014-0585-1) contains supplementary material, which is available to authorized users. Keywords:Tuberculous lymphadenitis, Tuberculous pleural effusion, M. tuberculosis, ICC, MPT64 antigen == Background == Tuberculosis (TB) is an important public health problem in Ethiopia. Relating to World Health Organization (WHO) statement of 2011, the estimated prevalence of TB instances in Ethiopia in 2010 2010 was 394 per 100,000 and Ethiopia rank eighth among the 22 high TB- burden countries [1]. Mycobacterium tuberculosis(M. tuberculosis) has the ability to colonize almost any site in the body and it can affect organs other than the lung such as; pleura, lymph nodes, belly, genitourinary tract, pores and skin, joints, bones and meninges [2],[3]. According to the TB and leprosy control system of Ethiopia, in the year 2010/2011, pulmonary TB accounts for 67.5% and extrapulmonary tuberculosis (EPTB) for 32.5% of all the new TB cases [4]. Probably the most prevalent type of EPTB is definitely tuberculous lymphadenitis (TBLN) [5],[6] with tuberculous pleuritis (TBP) becoming the second most frequent extrapulmonary manifestation [7],[8]. In spite of these high figures, the analysis of EPTB remains challenging for both clinicians and microbiologists [9],[10], because the disease presents in different ways and lack of diagnostic resources in developing countries adds to the problem. Analysis of EPTB is definitely difficult due to its paucibacillary nature and the irregular distribution of bacilli that cAMPS-Rp, triethylammonium salt tend to clump collectively resulting in very low level of sensitivity of conventional acidity fast bacilli (AFB) smear and tradition [11],[12]. A recent study has examined the performance of an immunocytochemical (ICC) staining method for the detection ofM. tuberculosiscomplex specific antigen; MPT64 in the analysis of EPTB. With this study ICC showed an overall level of sensitivity of 67.4% and a specificity of 95% [13]. MPT64 is definitely a 26-kd secreted protein produced byM. tuberculosiscomplex organisms, and this antigen has not been recognized in non-tuberculous mycobacteria. But, this antigen is definitely absent in BCG strains with RD2 deletion [14]. The aim of our study was to evaluate the cAMPS-Rp, triethylammonium salt diagnostic ability of ICC staining to diagnose TBLN and TBP from the detection ofM. tuberculosiscomplex specific antigen, MPT64 in a patient human population from Ethiopia and compare the results with standard methods i.e. Ziehl-Neelsen (ZN) cAMPS-Rp, triethylammonium salt staining and Lowenstein Jensen (LJ) tradition and polymerase chain reaction (PCR). == Methods == == Study design, participants and specimens == Individuals were included in the study from Tikur Anbessa Specialized Hospital and the United Vision Medical Solutions, Addis Ababa, Ethiopia from December 2011 to June 2012 by employing a cross-sectional study design. Pleural fluid specimens were collected consecutively from inpatients having a clinical analysis of TBP (n = 26), parapneumonic effusion (n = 14), pleural.