Rapid detection of tuberculosis in remote Alaska

ABSTRACT

In a remote region of western Alaska where tuberculosis (TB) incidence remains relatively high, a rapid molecular detection assay (Xpert MTB/RIF) was introduced four years ago with goal of improving the ability to diagnose active pulmonary tuberculosis (TB).  Our aggressive testing programme was intended for all patients acutely evaluated for pulmonary TB at our regional hospital and multiple clinics over a large area. All 223 consecutive patients evaluated for active pulmonary TB were tested with Xpert MTB/RIF (Xpert) per our protocol of which 192 (86.1%) had at least one additional (paired) sputum sample collected for standard acid-fast bacilli (smear) microscopy and culture. Fourteen patients eventually became culture-positive for Mycobacterium tuberculosis (MTB), all but one having initially tested positive (MTB detected) by Xpert (sensitivity 92.9%). All remaining culture-negative individuals had tested negative (not detected) by Xpert (specificity 100%). By contrast, smear microscopy sensitivity and specificity was 64.3% and 98.9% respectively.  This represents the addition of four active TB patients detected by Xpert over smear. In remote regions, the ability of Xpert to quickly and reliably detect TB while determine which patients are not contagious represents a huge healthcare savings as in most cases these patients will not require hospitalized isolation.

KEYWORDS:

• Alaska
• circumpolar health
• rapid molecular testing
• tuberculosis
• Xpert MTB/RIF

Acknowledgments

I wish to thank both Terri Hodges, MLT(ASCP) and Curtis Buchholz, MD, who were the Laboratory Manager and Lab Medical Director, respectively, during the study period. Their unwavering support and efforts early-on and throughout the study helped make rapid molecular detection possible in our resource limited healthcare situation. As always, Public Health Nursing in western Alaska stepped up and are to be commended for their tireless efforts in TB contact tracing and managing TB patients in our area.

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

The authors have not received any funding or benefits from industry or elsewhere to conduct this study.