542. Challenges in laboratory diagnosis Tuberculosis in the bacilloscopy laboratory at the Maputo Central Hospital
Session: Poster Abstract Session: Tuberculosis Epidemiology and Diagnosis
Thursday, October 27, 2016
Room: Poster Hall
Background: Ziehl-Neelsen stain is the preferred technique in Mozambique for the diagnosis of pulmonary TB. Triage, isolation and treatment of TB cases requires prompt laboratory data for case detection and monitoring for treatment failure. Each step needs to be performed correctly to maximize sensitivity including sputum collection, slide preparation and staining, reading and interpretation of results. When performed with at least two specimens, detection rate is 70-80% for pulmonary TB. Delayed diagnosis of tuberculosis is implicated as a cause of excess morbidity/mortality in our hospital. We reviewed several quality measures of the Maputo Central Hospital bacilloscopy lab (MCH-BL) including specimen provenance, quality, turnaround time, qualitative diagnostic results and number of repeat specimens sent following negative results.

Methods: Retrospective review of bacilloscopy results recorded in the 2014 National Tuberculosis Control Program laboratory registry.

Results: 3474 samples were processed at MCH-BL. Mean sample processing time was two hours from sample arrival to delivery of result. Saliva was the most common type (47%) followed by mucoid sputum (34%). Overall 7% of smears were positive and of these 60% were mucoid. 86% with initial negative had no second specimen requested.

Conclusion: Laboratory turnaround time was excellent. however,most respiratory samples were saliva and repeat specimens were not obtained for most of those with a negative initial specimen, which likely accounts for the low positivity rate. The hospital recently developed capacity for sputum induction, but staff training in expectorated specimen collection technique is needed. Further study with a diagnostic comparison standard (PCR or culture) is warranted to determine the sensitivity.

Pereira Zindoga, MD, MS, Pulmonary Medicine, Maputo Central Hospital, maputo, Mozambique


P. Zindoga, None

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