Abstract
B A C K G R O UND: Interferon-gamma release assays
(IGRAs) are reported to be more specific for the
diagnosis of latent tuberculous infection (LTBI) than
the tuberculin skin test (TST). The two-step procedure,
TST followed by an IGRA, is reported to be costeffective
in high-income countries, but it requires more
financial resources.
OBJ E C T I V E : To assess the added value of IGRA
compared to TST alone in the Netherlands.
METHODS: Test results and background data on
persons tested with an IGRA were recorded by the
Public Municipal Health Services in a web-based
database. The number of persons diagnosed with LTBI
using different screening algorithms was calculated.
RESULT S : In those tested with an IGRA, at least 60% of
persons who would have been diagnosed with LTBI
based on TST alone had a negative IGRA. Among those
with a TST reaction below the cut-off for the diagnosis
of LTBI, 13% had a positive IGRA. For 41% of persons
tested with an IGRA after TST, the IGRA influenced
whether or not an LTBI diagnosis would be made.
CONCLUSION: With the IGRA as reference standard, a
high proportion of persons in low-prevalence settings
are treated unnecessarily for LTBI if tested with TST
alone, while a small proportion eligible for preventive
treatment are missed. Incremental costs of the two-step
strategy seem to be balanced by the improved targeting
of preventive treatment.
(IGRAs) are reported to be more specific for the
diagnosis of latent tuberculous infection (LTBI) than
the tuberculin skin test (TST). The two-step procedure,
TST followed by an IGRA, is reported to be costeffective
in high-income countries, but it requires more
financial resources.
OBJ E C T I V E : To assess the added value of IGRA
compared to TST alone in the Netherlands.
METHODS: Test results and background data on
persons tested with an IGRA were recorded by the
Public Municipal Health Services in a web-based
database. The number of persons diagnosed with LTBI
using different screening algorithms was calculated.
RESULT S : In those tested with an IGRA, at least 60% of
persons who would have been diagnosed with LTBI
based on TST alone had a negative IGRA. Among those
with a TST reaction below the cut-off for the diagnosis
of LTBI, 13% had a positive IGRA. For 41% of persons
tested with an IGRA after TST, the IGRA influenced
whether or not an LTBI diagnosis would be made.
CONCLUSION: With the IGRA as reference standard, a
high proportion of persons in low-prevalence settings
are treated unnecessarily for LTBI if tested with TST
alone, while a small proportion eligible for preventive
treatment are missed. Incremental costs of the two-step
strategy seem to be balanced by the improved targeting
of preventive treatment.
| Original language | English |
|---|---|
| Pages (from-to) | 413-420 |
| Journal | International Journal of Tuberculosis and Lung Disease |
| Volume | 18 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 1 Jan 2014 |