Large-Scale Evaluation of Enzyme-Linked Immunospot Assay and Skin Test for Diagnosis of Mycobacterium tuberculosis Infection against a Gradient of Exposure in The Gambia

• Published in: Clinical infectious diseases Vol. 38; no. 7; pp. 966 - 973
• Main Authors: Hill, Philip C., Brookes, Roger H., Fox, Annette, Fielding, Katherine, Jeffries, David J., Jackson-Sillah, Dolly, Lugos, Moses D., Owiafe, Patrick K., Donkor, Simon A., Hammond, Abdulrahman S., Otu, Jacob K., Corrah, Tumani, Adegbola, Richard A., McAdam, Keith P. W. J.
• Format: Journal Article
• Language: English
• Published: Chicago, IL The University of Chicago Press 01.04.2004; University of Chicago Press
• Subjects: Adolescent; Adult; Aged; Antigens; Antigens, Bacterial - analysis; Bacterial diseases; Bacterial Proteins - analysis; Biological and medical sciences; Child; Child, Preschool; Cutaneous tuberculosis; Enzyme linked immunospot assay; Enzyme-Linked Immunosorbent Assay - methods; Female; Gambia; Human bacterial diseases; Humans; Infant; Infections; Infectious diseases; Major Articles; Male; Medical sciences; Middle Aged; Mycobacterium tuberculosis; Mycobacterium tuberculosis - isolation & purification; Rooms; Sensitivity and Specificity; Skin tests; Skin Tests - methods; Tuberculin; Tuberculin - analysis; Tuberculosis and atypical mycobacterial infections; Tuberculosis vaccine; Vaccination; Gambia; Africa; Costs; Mycobacterial infection; Negative result; Tuberculin PPD; Specificity; Smear; Bacteria; Diagnosis; Public health; Skin test; Human; Evaluation scale; Exploration; Infection; Antigen; Sensitivity; Tuberculosis; Mycobacterium tuberculosis; Mycobacteriales; Health economy; Sputum; Bacteriosis; Mycobacteriaceae; Actinomycetes; Comparative study
• ISSN: 1058-4838; 1537-6591; 1537-6591
• DOI: 10.1086/382362

The purified protein derivative (PPD) skin test for Mycobacterium tuberculosis infection lacks specificity. We assessed 2 more specific M. tuberculosis antigens (ESAT-6 and CFP-10) by enzyme-linked immunospot assay (ELISPOT) compared with PPD by ELISPOT and skin test in The Gambia. Of 735 household contacts of 130 sputum smear—positive tuberculosis cases, 476 (65%) tested positive by PPD ELISPOT, 300 (41%) tested positive by PPD skin test, and 218 (30%) tested positive by ESAT-6/CFP-10 ELISPOT. Only 15 (2%) had positive ESAT-6/CFP-10 results and negative PPD results by ELISPOT. With increasing M. tuberculosis exposure, the percentage of subjects who were PPD skin test positive/ESAT-6/CFP-10 ELISPOT negative increased (P < .001), whereas the percentage of subjects who were PPD skin test negative/PPD ELISPOT positive decreased (P = .011). Eighteen (31%) ESAT-6/CFP-10 ELISPOT–positive subjects in the lowest exposure category had negative PPD skin test results. ESAT-6/CFP-10 ELISPOT probably offers increased specificity in the diagnosis of M. tuberculosis infection in this tropical setting of endemicity, at the cost of some sensitivity.