Omar Bashir Ahmed Mohammed2018-08-062018-08-062006http://hdl.handle.net/123456789/12397Thesis submitted for fulfillments of M.Sc degree in Medical Laboratory Sciences ( Histopathological Techniques )Abstract Tuberculosis (TB) causes more deaths than any microbial disease. In spite of significant advances in prevention and drug treatment, TB still remains a major public health threat. So that there is a need for a rapid, sensitive, and more specific methods for TB diagnosis for effective and early treatment specially in areas of high number of visitors and immigrants like Makkah area in Western part of Saudi Arabia. TB was evaluated in 50 tissue specimens, taken from 50 patients in Makkah area. A polymerase chain reaction (PCR)-based assay and regular methods (acid-fast bacilli “AFB” stain, TB-culture, histopathology examination) were used. Results detected by all theses methods as follows: TB- PCR was positive in 32(64%), (AFB) stain was positive in l7(34%), TB-culture was positive in 30(60%), histological examination was positive in 26(52%). When done comparatively to the TB-culture, PCR for MT DNA in 50 tissue samples was 100% sensitive and 90% specific. AFB stain showed low sensitivity 50.0% and with specificity 90.0%, histological examination sensitivity was 80.0% and specificity 90.0%. These data indicate that PCR amplification is l.1S8fi1i for detecting MT DNA in histologic specimens as it is rapid and sensitive. Also it can be used to increase diagnostic accuracy in patients who have confusing diagnostic problems associated with granuloma tissue response. It also offers the possibility of the teclmique being carried out in fixed histologic specimens that may not identify the MT by regular methods.enPCRThesis