A rapid immunochromatographic assay for the detection of Mycobacterium tuberculosis antigens in pulmonary samples from HIV seropositive patients and its comparison with conventional methods.
As tuberculosis generates a highly heterogeneous antibody repertoire, its diagnosis requires tests based on cocktails of antigens. We describe a new, rapid method called rapid immunochromatographic assay (RICA) for cocktail-based diagnosis, which can detect Mycobacterial antigens in sputum specimens. Six antigenic fractions of pathogenic Mycobacterium tuberculosis were used in combination as the capture antigens in the control line of the flow-through assay. Antigen detection of 200 sputum samples from HIV seropositive patients by RICA assay gave a sensitivity of 97.9%, specificity of 99.0%, positive predictive value of 98.9%, negative predictive value of 98.0%, false positive rate of 0.9%, false negative rate of 2.0%, prevalence rate of 49%, likelihood ratio for positive results 97 and likelihood ratio for negative results 0.02. The combination of RICA and AFB staining gave a sensitivity of 100%, specificity of 100%, positive predictive value of 100%, negative predictive value of 100%, false positive rate of 0%, false negative rate of 0%, likelihood ratio for negative results 0. The assay was simple, rapid and economical for the detection of M. tuberculosis infection and suitable for large scale screening of samples in endemic areas without any sophisticated equipment. The results of the assay proved to be superior to conventional methods and combined with clinical data, could form the basis for starting an earlier course of treatment.
ICMR Virus Unit, Kolkata, ID and BG Hospital, GB4, 57 Dr. SC Banerjee Road Beliaghata, Kolkata 700010, India. nilanjan_19@yahoo.com
Nilanjan
N
Chakraborty
Sohinee
S
Bhattacharyya
Chandrav
C
De
Anirban
A
Mukherjee
Rathindra Nath
RN
Sarkar
Dipanjan
D
Banerjee
Sekhar
S
Chakraborti
Sujit Kumar
SK
Bhattacharyya
D000328:Adult; D000942:Antigens, Bacterial / Q000032:analysis* / Q000276:immunology; D005260:Female; D006679:HIV Seropositivity / Q000150:complications* / Q000276:immunology; D006801:Humans; D007163:Immunosorbent Techniques; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology / Q000302:isolation & purification*; D013183:Sputum / Q000737:chemistry / Q000276:immunology / Q000382:microbiology; D013194:Staining and Labeling / Q000379:methods*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000276:immunology / Q000382:microbiology
D000942:Antigens, Bacterial; C072681:Mycobacterium tuberculosis antigens