Rapid diagnosis of drug-resistant TB using line probe assays: from evidence to policy

Figures & data

Figure 1. Overview of the INNO-LiPA^® Rif. TB kit.

Image courtesy of Innogenetics NV, Gent, Belgium.

Modified with permission, © Innogenetics.

Figure 2. Overview of the GenoType^® MTBDRplus assay.

Image courtesy of Hain Lifescience GmbH, Nehren, Germany.

Modified with permission © Hain Lifescience.

Table 1. Findings from systematic reviews of commercial line probe assays for the diagnosis of drug-resistant tuberculosis.

Focus of the systematic review	Tests evaluated	Studies in the meta-analysis (n)	Specimens in the meta-analysis (n)	Studies that used the assay directly on clinical specimens (n)	Principal findings and conclusions	Ref.
Rapid detection of rifampicin resistance	INNO-LiPA^® Rif. TB assay	15	3349	4	12 out of 14 studies applying LiPA to isolates had a sensitivity greater than 95%, and 12 out of 14 had a specificity of 100%; the four studies that used clinical specimens had 100% specificity, and sensitivity ranged from 80 to 100%; overall, the LiPA assay was highly accurate when used on isolates; more evidence is needed on its accuracy when used directly on clinical specimens	[8]
Rapid detection of rifampicin and isoniazid resistance	GenoType^® MTBDR assay and GenoType MTBDRplus assay	14 for rifampicin15 for isoniazid	1738	9 for rifampicin10 for isoniazid	The pooled sensitivity (98.1%; 95% CI: 95.9– 99.1) and specificity (98.7%; 95% CI 97.3–99.4) estimates for rifampicin resistance were very high and consistent across all groups, assay versions and specimen types; the accuracy for isoniazid was variable, with sensitivity lower (84.3%; 95% CI: 76.6–89.8) and more inconsistent than specificity (99.5%; 95% CI: 97.5–99.9); overall, GenoType MDTBR assays had excellent accuracy for rifampicin resistance, even when used on clinical specimens; while specificity was excellent for isoniazid, sensitivity estimates were modest and variable	[9]

CI: Confidence interval.

Morgan M, Kalantri S, Flores L, Pai M. A commercial line probe assay for the rapid detection of rifampicin resistance in Mycobacterium tuberculosis: a systematic review and meta-analysis. BMC Infect. Dis.5, 62 (2005).

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Ling DI, Zwerling A, Pai M. GenoType MTBDR assays for the diagnosis of multidrug-resistant tuberculosis: a meta-analysis. Eur. Respir. J. DOI 10.1183/09031936.00061808 (2008) (Epub ahead of print).

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