Previous Article | Next Article 
Journal of Clinical Microbiology, January 1999, p. 229-232, Vol. 37, No. 1
0095-1137/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
Evaluation of the Abbott LCx Mycobacterium
tuberculosis Assay for Direct Detection of Mycobacterium
tuberculosis Complex in Human Samples
Maria Grazia
Garrino,1,*
Youri
Glupczynski,1
Josiane
Degraux,2
Henri
Nizet,1 and
Michel
Delmée2
Microbiology Laboratory, University Hospital
Mont-Godinne, Catholic University of Louvain,
Yvoir,1 and
Microbiology Unit,
Catholic University of Louvain, Brussels,2
Belgium
Received 27 July 1998/Returned for modification 2 September
1998/Accepted 24 September 1998
 |
ABSTRACT |
Seven hundred thirty-seven clinical samples from 460 patients were
processed for direct detection of Mycobacterium
tuberculosis complex by a semiautomated ligase chain reaction
commercial assay, the LCx Mycobacterium tuberculosis Assay
(LCx assay) from Abbott Laboratories. Results were compared to those of
direct microscopy and standard microbiological culture. Of 26 patients
(5.7%) with a culture positive for M. tuberculosis, 22 (84.6%) were found positive by the LCx assay. The sensitivity of the
LCx assay was 98% for smear-positive samples and 27% for
smear-negative samples. With an overall culture positivity rate for
M. tuberculosis of 8.3% (61 of 737 samples) and after
resolution of discrepant results according to clinical data, the
sensitivity, specificity, and positive and negative predictive values
of the LCx assay were 78, 100, 95, and 98%, respectively, compared to
85, 100, 100, and 98%, respectively, for culture and 67, 99, 87, and
97%, respectively, for acid-fast staining. In conclusion, the LCx
assay proved satisfactory and appears to be an easy-to-use 1-day test
which must be used with standard culture methods but can considerably
reduce diagnosis time versus culture. However, its clinical interest
appears to be limited in our population with low mycobacterial
prevalence because of its cost considering the small gain in
sensitivity versus direct microscopy.
| |
TEXT |
Rapid diagnosis of
Mycobacterium tuberculosis infection remains a challenge for
every medical laboratory. According to the current Centers for Disease
Control and Prevention recommendations, identification and
antimicrobial susceptibility testing should be available to clinicians
within 2 weeks (25). Direct microscopic examination is
straightforward but has poor sensitivity and does not allow
differentiation between tuberculous and nontuberculous mycobacteria
(NTM). Culture is sensitive and specific but very slow. In such a
setting, direct amplification tests (DAT) have been actively developed
and evaluated for the rapid diagnosis of mycobacterial diseases, and
two commercial assays, the Gen-Probe Mycobacterium
tuberculosis Direct Test (Gen-Probe, San Diego, Calif.) (1,
6, 15, 17, 21, 27) and the Amplicor M. tuberculosis
test (Roche Diagnostic Systems, Basel, Switzerland) (4, 5, 8, 10,
18, 23, 28), have already been approved by the Food and Drug
Administration for smear-positive specimens, after extensive
evaluations of their comparable performance characteristics.
Another amplification assay has been recently introduced, the LCx
Mycobacterium tuberculosis Assay (LCx assay) (Abbott
Laboratories, Chicago, Ill.), which is based on the ligase chain
reaction. This amplification assay uses a semiautomated system which
allows direct detection of M. tuberculosis in clinical
specimens (3, 13, 16, 19, 26).
The aim of this study was to assess prospectively the performance of
the LCx assay and compare its results with those of microscopic examination and culture for a large number of clinical specimens submitted to the laboratory for the diagnosis of mycobacterial infections.
Materials and methods.
From February to August 1997, we
prospectively investigated routine clinical specimens submitted for
diagnosis of mycobacterial disease from two university hospitals.
Specimens from patients under antituberculous treatment were not included.
All specimens were processed by the
N-acetyl-L-cysteine-NaOH
digestion-decontamination procedure (9). In all cases, half of the resuspended sediment was stored at 
20°C for the LCx assay, while the rest was used for acid-fast staining and inoculation onto
solid and liquid culture media. Smears were stained with auramine-rhodamine fluorochrome as a screening method, and positive smears were confirmed by Ziehl-Neelsen staining. Two solid slants were
inoculated per sample: Lowenstein-Jensen and Coletsos
(bioMérieux, Marcy l'Etoile, France). For the liquid medium,
BACTEC 12B medium (Becton Dickinson, Aalst, Belgium) was used in one
hospital, while the oxygen-sensitive fluorescent medium Mycobacterium
Growth Indicator Tube (Becton Dickinson) was employed at the other
hospital. Liquid and solid media were incubated at 37°C for 6 and 8 weeks, respectively, and were read twice a week. A culture was
considered positive if at least one of the media grew mycobacteria. In
addition to conventional biochemical tests, thin-layer chromatography
and gas-liquid chromatography were used for isolate identification (20). The LCx assay was performed in accordance with the
manufacturer's recommendations on a weekly basis (3).
When discrepancies were observed between the results of direct
staining, culture, and the LCx assay, the same decontaminated portion
of the specimen was retested by the LCx assay. If the discrepancy
persisted, clinical data and results obtained with additional samples
from the patient were analyzed. A specimen was considered truly
positive for M. tuberculosis when a culture positive for
M. tuberculosis was obtained or if a culture negative for
M. tuberculosis and a positive LCx assay result were
obtained if other concomitant material from the patient was
culture positive or if the patient's clinical history, including
chest roentgenograms and actual clinical presentation, was sufficiently
indicative of tuberculosis for empirical antituberculosis therapy. The
sensitivity, specificity, positive predictive value (PPV), and negative
predictive value (NPV) of the LCx assay were calculated and compared
with culture results and with culture results plus the patient's
clinical data.
Results.
A total of 737 samples were collected from 460 patients suspected of mycobacterial disease and processed by staining
methods, standard cultures, and the LCx assay to evaluate the assay's
ability to detect M. tuberculosis complex organisms. Six
hundred eighty-two were respiratory specimens from 425 patients,
including 280 sputum, 312 bronchial aspirate, 68 bronchoalveolar
lavage, 4 endotracheal aspiration, and 18 gastric juice aspirate
samples. The remaining 55 were nonrespiratory specimens from 35 patients, including 7 cerebrospinal fluid, 8 urine, and 40 exudate samples.
Seventy-one (9.6%) specimens of 737 from 32 (7%) of 460 patients were
positive for mycobacteria by culture. Isolates were
distributed as
follows: 61 (8.3%)
M. tuberculosis isolates from
26 patients (5.7%) and 10 NTM isolates from 6 patients (1.3%),
which
included 7
M. avium complex isolates, 2
M. simiae
isolates,
and 1
M. gordonae isolate.
Fifty-five samples were positive by fluorochrome staining, and all of
these were confirmed by acid-fast staining. Forty-six
(75.4%) of 61 samples whose culture yielded
M. tuberculosis were
positive
for acid-fast bacilli, as were 7 (70%) of 10 samples
which were
positive by culture for NTM. The two remaining smear-positive
samples
were culture
negative.
Among 59 samples found to be positive by the LCx assay, 49 from 22 patients were concomitantly positive for
M. tuberculosis by
culture. The details of the comparison of LCx assay results
with
culture results are shown in Table
1. A
higher sensitivity
was observed for smear-positive samples (97.8%
versus 26.7% for
smear-negative samples) and for respiratory specimens
(84.2% versus
25% for nonrespiratory specimens). None of the 10 samples growing
NTM were positive by the LCx assay.
Twenty-two samples gave rise to discrepant LCx assay and culture
results. Ten samples were LCx assay positive and culture
negative.
Seven were from a single patient who had been treated
for active
tuberculosis 2 years earlier with current clinical
suspicion of a
relapse; these samples were resolved as truly positive.
Two samples
were from a patient with other negative specimens
and with no signs of
tuberculosis, and the last sample, also from
a patient with other
negative specimens, was confirmed as negative
when reassayed. The
latter three results were considered false-positive
results of the LCx
assay.
On the other hand, 12 specimens originating from nine patients were
positive for
M. tuberculosis by culture and yielded negative
results with the LCx assay. All of these were considered false-negative
results of the LCx
assay.
Thirty-eight samples came from 15 human immunodeficiency
virus-seropositive patients. Seven patients had positive cultures
with
positive direct microscopy and were correctly diagnosed by
the LCx
assay (five patients with tuberculosis and two with other
mycobacterial
disease).
Table
2 summarizes the comparison of LCx
assay results with the resolved results (culture plus clinical data).
For an overall
sensitivity of 78%, there was still a significant
difference in
sensitivity between smear-positive and smear-negative
specimens
(98 versus 38%), while the difference between respiratory
and
nonrespiratory specimens was reduced (79 versus 70%).
The results of the LCx assay, culture, and microscopic examination were
then compared with the clinical resolved results for
the 737 specimens
(Table
3) from the 460 patients.
Seventy-two
specimens from 27 patients gave results consistent with a
clinical
diagnosis of tuberculosis. Sixty-one (85%) of 72 were
positive
for
M. tuberculosis by culture, 56 (78%) of 72 were positive by
LCx assay, and 48 (67%) of 72 were positive for
acid-fast bacilli.
Twenty-three (85%) patients of 27 with a diagnosis
of tuberculosis
were correctly diagnosed by the LCx assay, and 2 of
them had smear-negative
samples.
Discussion.
The LCx assay is a commercial, direct nucleic acid
amplification test, and it is among the first semiautomated tests,
along with the Roche Cobas Amplicor Mycobacterium
tuberculosis assay (11, 22, 30). Although DNA
extraction is still a long manual phase absorbing the major portion of
the manpower involved, the automation of the amplification,
hybridization, and detection steps offers significant advantages with a
hands-off time of about 2.5 h after specimen preparation. A run of
samples (20 clinical specimens and four controls) is completed in about
5 to 6 h.
Most of the studies evaluating different DAT include an excess of
positive specimens, which artificially increases prevalence
by
comparison with the real epidemiologic situation (
14). Thus,
sensitivity results according to culture and clinical diagnosis,
which
are reported in the recent literature, vary within a range
of 80 to
92% for home-made PCR (
1,
7,
12,
17,
24),
67 to 87% for
the Amplicor test (
8,
18,
28), 82 to 98%
for the GenProbe
direct test (
1,
15,
17,
21,
27,
28),
and 78 to 96% for the
LCx assay (
3,
13,
16,
26). For
all of these methods,
specificity is always excellent, within
96 to 100%. However, when the
prevalence of positive specimens
is closer to the real situation, the
sensitivity decreases to
86, 70, 71, and 77%, respectively, for
home-made PCR, the Amplicor
test, the Genprobe direct test, and the LCx
assay (
6,
7,
19,
23). We therefore decided not to include
samples from
patients undergoing active antituberculosis treatment
(
14).
With a prevalence of 8.3% of samples culture positive
for 5.9%
of patients with a clinical diagnosis of tuberculosis, the
performance
of the LCx assay in our evaluation (sensitivity of 78% and
specificity
of 99%) is very much in line with that in former studies
(
19).
When analyzing the discrepant results after resolution
according
to clinical data, three results were considered false
positives.
Contamination could be a reasonable explanation for one
sample,
because when the same DNA extract was reassayed, the sample was
negative. The other two specimens were from a patient with no
clinical
signs of tuberculosis. Sixteen specimens yielded false-negative
results
with the LCx assay. This could possibly be due to a low
number of
microorganisms and/or to their nonuniform distribution
in the clinical
samples. Indeed, six specimens were from patients
with previous
LCx-positive samples, which supports the assertion
that, as with smear
and culture analyses, more than one sample
from each patient should be
tested to allow sufficient accuracy
of detection of
M. tuberculosis in specimens by the LCx assay.
The 10 remaining
samples were from four patients for whom only
culture results allowed a
diagnosis of tuberculosis (smear negative
and LCx assay negative).
Hence, these results explain the low
sensitivity results (38%) we
obtained in our evaluation of smear-negative
specimens. On the other
hand, for two patients with smear-negative
specimens, an early
diagnosis of tuberculosis could be made thanks
to the positive LCx
assay results. However, in the first case,
we received additional
samples 2 days later with smear-positive
results so that, only 1 patient with smear-negative samples of
the 460 patients tested really
benefitted from this DAT in terms
of rapidity of diagnosis and
treatment instauration. The real
advantage of this test appeared for
smear-positive specimens because
NTM and
M. tuberculosis are
both readily detected by fluorescence
microscopy (
29) and
are almost impossible to distinguish by
smear alone. A diagnosis of
both tuberculosis and infection with
NTM should initially be considered
until a more definite diagnosis
can be made, especially in selected
populations, such as the AIDS
patient population. We received samples
from 15 human immunodeficiency
virus-infected patients, 7 of whom had
smear-positive samples.
Only two patients were infected with NTM and
were correctly diagnosed
by the LCx assay. In our study, the PPV of the
LCx assay for smear-positive
samples were found to be significantly
higher than that for smear-negative
samples (96 versus 33%) (Table
1),
as for the other approved
DAT (
2). Conversely, the PPVs of
smear and LCx assay results
were similar (87 and 95%, respectively)
(Table
3) because, unfortunately,
the proportion of specimens smear
positive for NTM was low in
the period chosen for the study. To really
benefit from the rapidity
afforded by a same-day automated method,
testing should be performed
every day. Although theoretically possible,
this is not practical
in most laboratories due to the cost. Hence, due
to the four controls
and calibrators for a run of a maximum of 20 specimens, the cost
per test, including reagents and manpower, varies
from about $30
if 20 specimens are processed together to $200 if a
single specimen
must be run alone. To perform this test on a daily
basis would
only be possible in reference or central laboratories. In
our
setting, it would be done only once a week, thus undermining a
great part of the argument for
rapidity.
We conclude that the LCx assay demonstrates very satisfactory
performance in terms of sensitivity and specificity for smear-positive
specimens, allowing rapid confirmation of positive smear results
as
true tuberculosis. Such features may be of considerable importance
for
laboratories dealing with a high proportion of infections
caused by
NTM, such as in the AIDS patient population. It offers
the advantage of
semiautomation, which saves labor and allows
a same-day result. On the
other hand, the assay's performance
obtained with specimens negative
by direct examination is not
sufficient to warrant its use on a routine
basis, and this test
cannot replace standard culture and susceptibility
testing for
mycobacteria. Moreover, the cost linked to calibrators and
controls
is such that this technology is probably suitable only for
reference
laboratories processing large series of specimens and having
good
communication with clinicians because of the possibility of both
false-positive and false-negative
results.
| |
FOOTNOTES |
*
Corresponding author. Mailing address: Microbiology
Laboratory, University Hospital Mont-Godinne, Ave. Therasse 1, B5530
Yvoir, Belgium. Phone: 32 81 423212. Fax: 32 81 423204. E-mail:
garrino{at}mblg.ucl.ac.be.
| |
REFERENCES |
| 1.
|
Abe, C.,
K. Hirano,
M. Wada,
Y. Kazumi,
M. Takahashi,
Y. Fukasawa,
T. Yoshimura,
C. Miyagi, and S. Goto.
1993.
Detection of Mycobacterium tuberculosis in clinical specimens by polymerase chain reaction and Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test.
J. Clin. Microbiol.
31:3270-3274[Abstract/Free Full Text].
|
| 2.
|
American Thoracic Society Workshop.
1997.
Rapid diagnostic tests for tuberculosis: what is the appropriate use?
Am. J. Respir. Crit. Care Med.
155:1804-1814[Abstract].
|
| 3.
|
Ausina, V.,
F. Gamboa,
E. Gazapo,
J. M. Manterola,
J. Lonca,
L. Matas,
J. R. Manzano,
C. Rodrigo,
P. J. Cardona, and E. Padilla.
1997.
Evaluation of the semiautomated Abbott LCx Mycobacterium tuberculosis assay for direct detection of Mycobacterium tuberculosis in respiratory specimens.
J. Clin. Microbiol.
35:1996-2002[Abstract].
|
| 4.
|
Beavis, K. G.,
M. B. Lichty,
D. L. Jungkind, and O. Giger.
1995.
Evaluation of Amplicor PCR for direct detection of Mycobacterium tuberculosis from sputum specimens.
J. Clin. Microbiol.
33:2582-2586[Abstract].
|
| 5.
|
Bergmann, J. S., and G. L. Woods.
1996.
Clinical evaluation of the Roche AMPLICOR PCR Mycobacterium tuberculosis test for detection of M. tuberculosis in respiratory specimens.
J. Clin. Microbiol.
34:1083-1085[Abstract].
|
| 6.
|
Bodmer, T.,
A. Gurtner,
K. Schopfer, and L. Matter.
1994.
Screening of respiratory tract specimens for the presence of Mycobacterium tuberculosis by using the Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test.
J. Clin. Microbiol.
32:1483-1487[Abstract/Free Full Text].
|
| 7.
|
Clarridge, J. E.,
R. M. Shawar,
T. M. Shinnick, and B. B. Plikaytis.
1993.
Large-scale use of polymerase chain reaction for detection of Mycobacterium tuberculosis in a routine mycobacteriology laboratory.
J. Clin. Microbiol.
31:2049-2056[Abstract/Free Full Text].
|
| 8.
|
D'Amato, R. F.,
A. A. Wallman,
L. H. Hochstein,
P. M. Colaninno,
M. Scardamaglia,
E. Ardila,
M. Ghouri,
K. Kim,
R. C. Patel, and A. Miller.
1995.
Rapid diagnosis of pulmonary tuberculosis by using Roche AMPLICOR Mycobacterium tuberculosis PCR test.
J. Clin. Microbiol.
33:1832-1834[Abstract].
|
| 9.
|
Della-Latta, P., and I. Weitzman.
1998.
Mycobacteriology, p. 169-203.
In
H. D. Isenberg (ed.), Essential procedures for clinical microbiology. ASM Press, Washington, D.C.
|
| 10.
|
Devallois, A.,
E. Legrand, and N. Rastogi.
1996.
Evaluation of Amplicor MTB test as adjunct to smears and culture for direct detection of Mycobacterium tuberculosis in the French Caribbean.
J. Clin. Microbiol.
34:1065-1068[Abstract].
|
| 11.
|
Eing, B. R.,
A. Becker,
A. Sohns, and R. Ringelmann.
1998.
Comparison of Roche Cobas Amplicor Mycobacterium tuberculosis assay with in-house PCR and culture for detection of M. tuberculosis.
J. Clin. Microbiol.
36:2023-2029[Abstract/Free Full Text].
|
| 12.
|
Forbes, B. A., and K. E. Hicks.
1994.
Ability of PCR assay to identify Mycobacterium tuberculosis in BACTEC 12B vials.
J. Clin. Microbiol.
32:1725-1728[Abstract/Free Full Text].
|
| 13.
|
Gamboa, F.,
J. Dominguez,
E. Padilla,
J. M. Manterola,
E. Gazapo,
J. Lonca,
L. Matas,
A. Hernandez,
P. J. Cardona, and V. Ausina.
1998.
Rapid diagnosis of extrapulmonary tuberculosis by ligase chain reaction amplification.
J. Clin. Microbiol.
36:1324-1329[Abstract/Free Full Text].
|
| 14.
|
Ieven, M., and H. Goossens.
1997.
Relevance of nucleic acid amplification techniques for diagnosis of respiratory tract infections in the clinical laboratory.
Clin. Microbiol. Rev.
10:242-256[Abstract].
|
| 15.
|
Jonas, V.,
M. J. Alden,
J. I. Curry,
K. Kamisango,
C. A. Knott,
R. Lankford,
J. M. Wolfe, and D. F. Moore.
1993.
Detection and identification of Mycobacterium tuberculosis directly from sputum sediments by amplification of rRNA.
J. Clin. Microbiol.
31:2410-2416[Abstract/Free Full Text].
|
| 16.
|
Lindbrathen, A.,
P. Gaustad,
B. Hovig, and T. Tonjum.
1997.
Direct detection of Mycobacterium tuberculosis complex in clinical samples from patients in Norway by ligase chain reaction.
J. Clin. Microbiol.
35:3248-3253[Abstract].
|
| 17.
|
Miller, N.,
S. G. Hernandez, and T. J. Cleary.
1994.
Evaluation of Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test and PCR for direct detection of Mycobacterium tuberculosis in clinical specimens.
J. Clin. Microbiol.
32:393-397[Abstract/Free Full Text].
|
| 18.
|
Moore, D. F., and J. I. Curry.
1995.
Detection and identification of Mycobacterium tuberculosis directly from sputum sediments by Amplicor PCR.
J. Clin. Microbiol.
33:2686-2691[Abstract].
|
| 19.
|
Moore, D. F., and J. I. Curry.
1998.
Detection and identification of Mycobacterium tuberculosis directly from sputum sediments by ligase chain reaction.
J. Clin. Microbiol.
36:1028-1031[Abstract/Free Full Text].
|
| 20.
|
Parez, J. J.,
M. Fauville Dufaux,
J. L. Dossogne,
E. de Hoffmann, and F. Pouthier.
1994.
Faster identification of mycobacteria using gas liquid and thin layer chromatography.
Eur. J. Clin. Microbiol. Infect. Dis.
13:717-725[Medline].
|
| 21.
|
Pfyffer, G. E.,
P. Kissling,
R. Wirth, and R. Weber.
1994.
Direct detection of Mycobacterium tuberculosis complex in respiratory specimens by a target-amplified test system.
J. Clin. Microbiol.
32:918-923[Abstract/Free Full Text].
|
| 22.
|
Rajalahti, I.,
P. Vuorinen,
M. M. Nieminen, and A. Miettinen.
1998.
Detection of Mycobacterium tuberculosis complex in sputum specimens by the automated Roche Cobas Amplicor Mycobacterium Tuberculosis test.
J. Clin. Microbiol.
36:975-978[Abstract/Free Full Text].
|
| 23.
|
Schirm, J.,
L. A. Oostendorp, and J. G. Mulder.
1995.
Comparison of Amplicor, in-house PCR, and conventional culture for detection of Mycobacterium tuberculosis in clinical samples.
J. Clin. Microbiol.
33:3221-3224[Abstract].
|
| 24.
|
Shawar, R. M.,
F. A. el Zaatari,
A. Nataraj, and J. E. Clarridge.
1993.
Detection of Mycobacterium tuberculosis in clinical samples by two-step polymerase chain reaction and nonisotopic hybridization methods.
J. Clin. Microbiol.
31:61-65[Abstract/Free Full Text].
|
| 25.
|
Tenover, F. C.,
J. T. Crawford,
R. E. Huebner,
L. J. Geiter,
C. R. Horsburgh, Jr., and R. C. Good.
1993.
The resurgence of tuberculosis: is your laboratory ready?
J. Clin. Microbiol.
31:767-770[Free Full Text].
|
| 26.
|
Tortoli, E.,
F. Lavinia, and M. T. Simonetti.
1997.
Evaluation of a commercial ligase chain reaction kit (Abbott LCx) for direct detection of Mycobacterium tuberculosis in pulmonary and extrapulmonary specimens.
J. Clin. Microbiol.
35:2424-2426[Abstract].
|
| 27.
|
Vlaspolder, F.,
P. Singer, and C. Roggeveen.
1995.
Diagnostic value of an amplification method (Gen-Probe) compared with that of culture for diagnosis of tuberculosis.
J. Clin. Microbiol.
33:2699-2703[Abstract].
|
| 28.
|
Vuorinen, P.,
A. Miettinen,
R. Vuento, and O. Hallstrom.
1995.
Direct detection of Mycobacterium tuberculosis complex in respiratory specimens by Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test and Roche Amplicor Mycobacterium Tuberculosis Test.
J. Clin. Microbiol.
33:1856-1859[Abstract].
|
| 29.
|
Wright, P. W.,
R. J. Wallace,
N. W. Wright,
B. A. Brown, and D. E. Griffith.
1998.
Sensitivity of fluorochrome microscopy for detection of Mycobacterium tuberculosis versus nontuberculous mycobacteria.
J. Clin. Microbiol.
36:1046-1049[Abstract/Free Full Text].
|
| 30.
|
Yuen, K. Y.,
W. C. Yam,
L. P. Wong, and W. H. Seto.
1997.
Comparison of two automated DNA amplification systems with a manual one-tube nested PCR assay for diagnosis of pulmonary tuberculosis.
J. Clin. Microbiol.
35:1385-1389[Abstract].
|
Journal of Clinical Microbiology, January 1999, p. 229-232, Vol. 37, No. 1
0095-1137/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
-
Piersimoni, C., Scarparo, C.
(2003). Relevance of Commercial Amplification Methods for Direct Detection of Mycobacterium tuberculosis Complex in Clinical Samples. J. Clin. Microbiol.
41: 5355-5365
[Full Text]
-
Mazzarelli, G., Rindi, L., Piccoli, P., Scarparo, C., Garzelli, C., Tortoli, E.
(2003). Evaluation of the BDProbeTec ET System for Direct Detection of Mycobacterium tuberculosis in Pulmonary and Extrapulmonary Samples: a Multicenter Study. J. Clin. Microbiol.
41: 1779-1782
[Abstract]
[Full Text]
-
Shetty, N, Shemko, M, Holton, J, Scott, G M
(2000). Is the detection of Mycobacterium tuberculosis DNA by ligase chain reaction worth the cost: experiences from an inner London teaching hospital. J. Clin. Pathol.
53: 924-928
[Abstract]
[Full Text]
-
O'Connor, T M, Sheehan, S, Cryan, B, Brennan, N, Bredin, C P
(2000). The ligase chain reaction as a primary screening tool for the detection of culture positive tuberculosis. Thorax
55: 955-957
[Abstract]
[Full Text]
-
Lumb, R., Davies, K., Dawson, D., Gibb, R., Gottlieb, T., Kershaw, C., Kociuba, K., Nimmo, G., Sangster, N., Worthington, M., Bastian, I.
(1999). Multicenter Evaluation of the Abbott LCx Mycobacterium tuberculosis Ligase Chain Reaction Assay. J. Clin. Microbiol.
37: 3102-3107
[Abstract]
[Full Text]
Top
Abstract
Text
