High level of discordant IGRA results in HIV-infected adults and children.
METHODS
Tygerberg district, Western Cape Province, South Africa.


OBJECTIVE
To measure the agreement of two interferon-gamma release assays (IGRAs) and the tuberculin skin test (TST) for the detection of Mycobacterium tuberculosis infection in human immunodeficiency virus (HIV) infected adults and children in a setting highly endemic for tuberculosis (TB).


METHODS
Cross-sectional study.


RESULTS
In HIV-infected adults (n=20) and children (n=23), tests yielded discordant results, with 61% of individuals testing positive with T-SPOT.TB, 41% with TST and 28% with QuantiFERON TB Gold (QTF). In children, there was poor agreement between the TST and T-SPOT.TB (kappa [kappa]=-0.02), but moderate agreement between the TST and QTF (kappa=0.44). In adults, there was moderate agreement between the TST and T-SPOT.TB (kappa=0.43), and the TST and QTF (kappa = 0.46). In children and adults, there was fair agreement between the T-SPOT.TB and QTF (kappa=0.33). Twenty per cent of adults had >or=1 indeterminate IGRA results.


CONCLUSIONS
There is poor to moderate agreement between the TST and IGRAs in HIV-infected adults and children. T-SPOT.TB may have improved sensitivity for detection of M. tuberculosis infection in HIV-infected individuals compared to the QTF and the TST. In HIV-infected individuals, IGRA test properties are affected by test cut-off point and nil control responses.
Mandalakas
A M
AM
Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA. anna.mandalakas@case.edu
Hesseling
A C
AC
Chegou
N N
NN
Kirchner
H L
HL
Zhu
X
X
Marais
B J
BJ
Black
G F
GF
Beyers
N
N
Walzl
G
G
D017088:AIDS-Related Opportunistic Infections / Q000175:diagnosis*; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D003430:Cross-Sectional Studies; D015658:HIV Infections / Q000150:complications; D006801:Humans; D007159:Immunologic Tests; D007371:Interferon-gamma / Q000097:blood*; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D013019:South Africa / Q000453:epidemiology; D014374:Tuberculin Test; D014376:Tuberculosis / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D007371:Interferon-gamma