Urine lipoarabinomannan point-of-care testing in patients affected by pulmonary nontuberculous mycobacteria - experiences from the Danish Cystic Fibrosis cohort study
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Urine lipoarabinomannan point-of-care testing in patients affected by pulmonary nontuberculous mycobacteria - experiences from the Danish Cystic Fibrosis cohort study. / Qvist, Tavs; Johansen, Isik S.; Pressler, Tania; Høiby, Niels; Andersen, Aase B.; Katzenstein, Terese L.; Bjerrum, Stephanie.
In: BMC Infectious Diseases, Vol. 14, 655, 04.12.2014, p. 1-8.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Urine lipoarabinomannan point-of-care testing in patients affected by pulmonary nontuberculous mycobacteria - experiences from the Danish Cystic Fibrosis cohort study
AU - Qvist, Tavs
AU - Johansen, Isik S.
AU - Pressler, Tania
AU - Høiby, Niels
AU - Andersen, Aase B.
AU - Katzenstein, Terese L.
AU - Bjerrum, Stephanie
PY - 2014/12/4
Y1 - 2014/12/4
N2 - Background: The urine lipoarabinomannan (LAM) strip test has been suggested as a new point-of-care test for active tuberculosis (TB) among human immunodeficiency virus (HIV) infected individuals. It has been questioned if infections with nontuberculous mycobacteria (NTM) affect assay specificity. We set forth to investigate if the test detects LAM in urine from a Danish cystic fibrosis (CF) population characterized by a high NTM prevalence and negligible TB exposure. Method: Patients followed at the Copenhagen CF Center were comprehensively screened for pulmonary NTM infection between May 2012 and December 2013. Urine samples were tested for LAM using the 2013 Determine™ TB LAM Ag strip test. Results: Three-hundred and six patients had a total of 3,322 respiratory samples cultured for NTM and 198 had urine collected (65%). A total of 23/198 (12%) had active pulmonary NTM infection. None had active TB. The TB-LAM test had an overall positive rate of 2.5% applying a grade 2 cut-point as positivity threshold, increasing to 10.6% (21/198) if a grade 1 cut-point was applied. Among patients with NTM infection 2/23 (8.7%) had a positive LAM test result at the grade 2 cut-point and 9/23 (39.1%) at the grade 1 cut -point. Test specificity for NTM diagnosis was 98.3% and 93.1 for grade 2 and 1 cut-point respectively. Conclusions: This is the first study to assess urine LAM detection in patients with confirmed NTM infection. The study demonstrated low cross-reactivity due to NTM infection when using the recommended grade 2 cut-point as positivity threshold. This is reassuring in regards to interpretation of the LAM test for TB diagnosis in a TB prevalent setting. The test was not found suitable for NTM detection among patients with CF.
AB - Background: The urine lipoarabinomannan (LAM) strip test has been suggested as a new point-of-care test for active tuberculosis (TB) among human immunodeficiency virus (HIV) infected individuals. It has been questioned if infections with nontuberculous mycobacteria (NTM) affect assay specificity. We set forth to investigate if the test detects LAM in urine from a Danish cystic fibrosis (CF) population characterized by a high NTM prevalence and negligible TB exposure. Method: Patients followed at the Copenhagen CF Center were comprehensively screened for pulmonary NTM infection between May 2012 and December 2013. Urine samples were tested for LAM using the 2013 Determine™ TB LAM Ag strip test. Results: Three-hundred and six patients had a total of 3,322 respiratory samples cultured for NTM and 198 had urine collected (65%). A total of 23/198 (12%) had active pulmonary NTM infection. None had active TB. The TB-LAM test had an overall positive rate of 2.5% applying a grade 2 cut-point as positivity threshold, increasing to 10.6% (21/198) if a grade 1 cut-point was applied. Among patients with NTM infection 2/23 (8.7%) had a positive LAM test result at the grade 2 cut-point and 9/23 (39.1%) at the grade 1 cut -point. Test specificity for NTM diagnosis was 98.3% and 93.1 for grade 2 and 1 cut-point respectively. Conclusions: This is the first study to assess urine LAM detection in patients with confirmed NTM infection. The study demonstrated low cross-reactivity due to NTM infection when using the recommended grade 2 cut-point as positivity threshold. This is reassuring in regards to interpretation of the LAM test for TB diagnosis in a TB prevalent setting. The test was not found suitable for NTM detection among patients with CF.
KW - Abscessus
KW - Avium
KW - CF
KW - LAM
KW - Lipoarabinomannan
KW - Nontuberculous
KW - NTM
UR - http://www.biomedcentral.com/1471-2334/14/655
U2 - 10.1186/s12879-014-0655-4
DO - 10.1186/s12879-014-0655-4
M3 - Journal article
AN - SCOPUS:84923930509
VL - 14
SP - 1
EP - 8
JO - B M C Infectious Diseases
JF - B M C Infectious Diseases
SN - 1471-2334
M1 - 655
ER -
ID: 140022466