Vol.2 No.08 -1 : Comparative Study between Polymerase Chain Reaction and Different Rapid Tests for Detection of Mycobacterium Infection.

By : Elarabany N. F1, Abdallah, A. E.1, Abdallah, G. A.2, and Salah A.2.

Abstract

The objective of this work is to reach a sensitive and rapid method for the laboratory diagnosis of active tuberculosis disease in patients and latent TB infection in household contacts and healthy community controls. We recruited 86 subjects divided into 3 groups: Thirty six patients with suspected active TB (Twenty four suspected pulmonary TB cased and 12 suspected extrapulmonary TB cases). 28 household contacts of confirmed pulmonary TB patients and 22 healthy community controls. Methods: For diagnosis of active tuberculosis the following tests were evaluated: Ziehl-Neelsen (Z-N) staining and culture on Lownestein-Jensen (L-j), tuberculin skin test (TST), nested polymerase chain reaction (PCR) assay on separated peripheral blood mononuclear cells (PBMCs), antibody detection by Immunchromatographic test (ICT), and JFN assay by QuantiFERON TB Gold In-Tube method for diagnosis of latent tuberculosic the following tests were evaluated: TST and Quantiferon TB Gold (In-tube method). The results showed that in pulmonary TB group, TST was the most sensitive test (92.3%), while QFT-Gold IT plus ZN was the most sensitive combined test (100%). In extrapulmonary TB group, TST, nested PCR and QFT-Gold IT were the most sensitive single tests (75%) while QFT-Gold IT plus ZN was the most sensitive combines test (100%). For diagnosis of LTBI: QFT-Gold IT was as sensitive as the TST. TST was 54.5% specific, while QFT Gold-IT was 94.5% specific TST showed that the exposure in the contacts group increased the risk of infection in the contacts group 0.9 times more than the control group (OR, 0,9m 95% Cl, 0.25-3.22; P=0.85). by QFT-Gold IT, exposure increased the risk of infection in the contacts group 8.4 times more than the control group (OR, 8.4; 95% Cl, 0.9-195.63; P=0.028). In household contacts group the concordance between TST and QFT-Gold IT was poor (64.3%, with a k value of 0.230.18). In conclusion, using QFT-Gold IT plus ZN staining is very helpful in the diagnosis of active TB disease. For diagnosis of LTBl. QuantiFERON-TB Gold In-Tube method is more helpful than Tuberculin skin test.

1_Comparative_Study_between_Polymerase_Chain_Reaction_and_Different_Rapid_Tests_for_Detection_of_Mycobacterium_Infection
Download Issue