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The clinical utility of the urine-based lateral flow lipoarabinomannan assay in HIV-infected adults in Myanmar: an observational study.

The clinical utility of the urine-based lateral flow lipoarabinomannan assay in HIV-infected adults in Myanmar: an observational study.
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Thit SS, Aung NM, Htet ZW, Boyd MA, Saw HA, Anstey NM, Kyi TT, Cooper DA, Kyi MM, Hanson J,


Thit SS, Aung NM, Htet ZW, Boyd MA, Saw HA, Anstey NM, Kyi TT, Cooper DA, Kyi MM, Hanson J, (click to view)

Thit SS, Aung NM, Htet ZW, Boyd MA, Saw HA, Anstey NM, Kyi TT, Cooper DA, Kyi MM, Hanson J,

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BMC medicine 2017 08 0415(1) 145 doi 10.1186/s12916-017-0888-3

Abstract
BACKGROUND
The use of the point-of-care lateral flow lipoarabinomannan (LF-LAM) test may expedite tuberculosis (TB) diagnosis in HIV-positive patients. However, the test’s clinical utility is poorly defined outside sub-Saharan Africa.

METHODS
The study enrolled consecutive HIV-positive adults at a tertiary referral hospital in Yangon, Myanmar. On enrolment, patients had a LF-LAM test performed according to the manufacturer’s instructions. Clinicians managing the patients were unaware of the LF-LAM result, which was correlated with the patient’s clinical course over the ensuing 6 months.

RESULTS
The study enrolled 54 inpatients and 463 outpatients between July 1 and December 31, 2015. On enrolment, the patients’ median (interquartile range) CD4 T-cell count was 270 (128-443) cells/mm(3). The baseline LF-LAM test was positive in 201/517 (39%). TB was confirmed microbiologically during follow-up in 54/517 (10%), with rifampicin resistance present in 8/54 (15%). In the study’s resource-limited setting, extrapulmonary testing for TB was not possible, but after 6 months, 97/201 (48%) with a positive LF-LAM test on enrolment had neither died, required hospitalisation, received a TB diagnosis or received empirical anti-TB therapy, suggesting a high rate of false-positive results. Of the 97 false-positive tests, 89 (92%) were grade 1 positive, suggesting poor test specificity using this cut-off. Only 21/517 (4%) patients were inpatients with TB symptoms and a CD4 T-cell count of < 100 cells/mm(3). Five (24%) of these 21 died, three of whom had a positive LF-LAM test on enrolment. However, all three received anti-TB therapy before death - two after diagnosis with Xpert MTB/RIF testing, while the other received empirical treatment. It is unlikely that knowledge of the baseline LF-LAM result would have averted any of the study's other 11 deaths; eight had a negative test, and of the three patients with a positive test, two received anti-TB therapy before death, while one died from laboratory-confirmed cryptococcal meningitis. The test was no better than a simple, clinical history excluding TB during follow-up (negative predictive value (95% confidence interval): 94% (91-97) vs. 94% (91-96)). CONCLUSIONS
The LF-LAM test had limited clinical utility in the management of HIV-positive patients in this Asian referral hospital setting.

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