Table 2.

Characteristics of nine patients with concordant positive TST and IGRA and discordant TST and IGRA

N	TST	IGRA	BCG	Tuberculosis exposure	CD4+ count (cells/mm3)	Medication (daily dose in mg)	Diagnosis
Concordant positive results of TST and IGRA
1	pos.	pos.	no	yes	748	MTX 12.5; lef 20	PsA
2	pos.	pos.	no	yes	972	MTX 25	RA
3	pos.	pos.	no	yes	N.A.	none	AS
Discordant results of TST and IGRA
1	neg.	pos.	no	yes	974	MTX 15	RA
2	pos.	neg.	yes	no	590	pred 5; MTX 10; lef 20	RA
3	pos.	neg.	yes	no	387	MTX 25	RA
4	pos.	neg.	yes	no	2,050	MTX 7.5	PsA
5	pos.	neg.	no	yes	632	none	AS
6	pos.	neg.	no	yes	549	MTX 7.5	RA

N patient number, TST tuberculosis skin test, IGRA interferon-gamma release assay (Quantiferon-TB Gold), BCG Bacillus Calmette–Guérin, TB tuberculosis, CD4 ⁺ count CD4⁺ T lymphocyte cell count, pos. positive, neg. negative, N.A. not available, MTX methotrexate, pred prednisone, lef leflunomide, PsA psoriatic arthritis, RA rheumatoid arthritis, AS ankylosing spondylitis