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.
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;
+4 more...Otu, Jacob K;
Corrah, Tumani;
Adegbola, Richard A;
McAdam, Keith PWJ;
(2004)
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.
Clinical infectious diseases, 38 (7).
pp. 966-973.
ISSN 1058-4838
DOI: https://doi.org/10.1086/382362
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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.
