Preliminary performance of the VIDAS TB-IGRA as an aid in the diagnosis of individuals infected with Mycobacterium tuberculosis

Abstract

This preliminary study compares VIDAS TB-IGRA (bioMérieux, Marcy-l'Etoile, France) with the established QuantiFERON-TB Gold Plus (QFT-Plus) (Qiagen, Hilden, Germany) to evaluate diagnostic performance for the diagnosis of individuals infected with Mycobacterium tuberculosis complex (latent infection and disease). The study was multi-center and performed between 2 October 2019 and 4 February 2020. Participants were divided into tuberculosis (TB) disease, high-risk, and low-risk populations. The confirmed TB disease population included 104 patients. The high-risk population included 162 individuals with flagged risk factors on a questionnaire but without objective clinical confirmation of TB. The low-risk population included 117 healthy blood donors from the French National Blood Bank. Positive and negative percent agreement (PPA and NPA) were determined between the VIDAS TB-IGRA and QFT-Plus. In the TB disease population, sensitivity was measured against bacterial culture and PCR. The VIDAS TB-IGRA produced fewer indeterminate results than the QFT-Plus (1/104 vs 23/104) in the TB disease population and exhibited a sensitivity of 95.0% against bacterial culture. Furthermore, a 98.2% PPA was obtained in comparison to QFT-Plus. In the low-risk population, the VIDAS TB-IGRA demonstrated high specificity (94.9%) and a strong NPA (98.2%) compared to QFT-Plus. In the high-risk population, the VIDAS TB-IGRA exhibited a strong PPA (94.4%) with the QFT-Plus. A lower NPA was observed (85.2%) compared to QFT-Plus, which may be due to a higher sensitivity demonstrated in the TB disease population. The fully automated VIDAS TB-IGRA is a promising aid in the diagnosis of individuals infected with Mycobacterium tuberculosis (latent infection and active disease). It exhibits higher sensitivity while maintaining specificity and produces fewer indeterminate interpretations than QFT-Plus. Its easy-to-use, single-patient format may lead to increased TB testing to aid in the adequate diagnosis and management of the disease.IMPORTANCEThis study presents a comprehensive evaluation of the VIDAS TB-IGRA diagnostic test. This test is compared with the established QuantiFERON-TB Gold Plus to assess its effectiveness in diagnosing both latent and active tuberculosis (TB) infections. The study highlights the VIDAS TB-IGRA's higher sensitivity, fewer indeterminate results, and robust performance across different patient populations, including those with confirmed TB disease, high-risk, and low-risk groups. The findings suggest that the VIDAS TB-IGRA could enhance TB diagnosis and management, offering a fully automated, easy-to-use solution that reduces human error and result variability.

Keywords: IGRA; Mycobacterium tuberculosis complex; QFT-Plus; VIDAS.

Fig 1

Patient study inclusion criteria. (A) Flow diagram for the inclusion of TB disease population. (B) Flow diagram for the inclusion of low-risk population. (C) Flow diagram for the inclusion of high-risk population.

Fig 2

VIDAS TB-IGRA workflow.

Fig 3

Comparison between the VIDAS TB-IGRA and QFT-Plus for the tuberculosis disease population. (A) Sample numbers, sensitivity, and positive predictive agreement. (B) Patient sample IFN-γ concentrations for the VIDAS TB-IGRA and QFT-Plus on AG-NIL intermediate result. (C) Patient sample IFN-γ concentrations for the VIDAS TB-IGRA and QFT-Plus on NIL intermediate result. (D) Patient sample IFN-γ concentrations for the VIDAS TB-IGRA and QFT-Plus on AG-NIL intermediate result. Nil, QFT-Plus negative control; NIL, VIDAS TB-IGRA negative control; Mitogen, QFT-Plus positive control; MIT-NIL, VIDAS TB-IGRA positive control; TB1/TB2, QFT-Plus mitogenic response samples; AG-NIL, VIDAS TB-IGRA mitogenic response sample. The dotted lines represent the sample threshold values for the respective assay. FN, false negatives; NEG, negatives; POS, positives; and TP, total positives. McNemar’s test for paired data was used to determine statistical significance (P < 0.0001).

Fig 4

Comparison between the VIDAS TB-IGRA and QFT-Plus for the low-risk population. (A) Specificity estimates for the two assays. (B) Sample numbers and NPA. (C) Patient sample interferon-γ concentrations for the VIDAS TB-IGRA and QFT-Plus on AG-NIL intermediate result. (D) Patient sample interferon-γ concentrations for the VIDAS TB-IGRA and QFT-Plus on NIL intermediate result. (E) Patient sample interferon-γ concentrations for the VIDAS TB-IGRA and QFT-Plus on MIT-NIL intermediate result. Nil, QFT-Plus negative control; NIL, VIDAS TB-IGRA negative control; Mitogen, QFT-Plus positive control; MIT-NIL, VIDAS TB-IGRA positive control; TB1/TB2, QFT-Plus mitogenic response samples; and AG-NIL, VIDAS TB-IGRA mitogenic response sample. The dotted lines represent the sample threshold values for the respective assay.

Fig 5

Comparison between the VIDAS TB-IGRA and QFT-Plus for the high-risk population. (A) Subgroups’ description. (B) Sample numbers, PPA, and NPA. (C) Patient sample interferon-γ concentrations for the VIDAS TB-IGRA and QFT-Plus for AG-NIL intermediate result. (D) Patient sample interferon-γ concentrations for the VIDAS TB-IGRA and QFT-Plus for NIL intermediate result. (E) Patient sample interferon-γ concentrations for the VIDAS TB-IGRA and QFT-Plus for MIT-NIL intermediate result. Nil, QFT-Plus negative control; NIL, VIDAS TB-IGRA negative control; Mitogen, QFT-Plus positive control; MIT-NIL, VIDAS TB-IGRA positive control; TB1/TB2, QFT-Plus mitogenic response samples; and AG-NIL, VIDAS TB-IGRA mitogenic response sample. The dotted lines represent the sample threshold values for the respective assay. A Wilcoxon’s test for paired data was used to determine statistical significance between VIDAS TB-IGRA and QFT Plus for the response AG-NIL (P < 0.0001 for both TB1 and TB2).