Skip to main content

Free Content Bulk acid-fast staining of sputum smears: time to end a taboo

Download Article:
(PDF 227.2939453125 kb)
SETTING: A high-throughput laboratory routinely performing fluorescence microscopy for acid-fast bacilli (AFB) smear with automated bulk staining.

OBJECTIVES: To determine the risk of false-positive AFB sputum smears from bulk staining showing as smear-positive, culture-negative specimens, or a decrease in smear- and culture-positives.

DESIGN: Direct AFB smear and Löwenstein-Jensen culture were performed for a total of 39 350 routine sputum specimens. Of these, 6633 were randomly selected for individual AFB staining, while the remaining 32 717 were processed by bulk machine staining. Positives for smear and culture were compared.

RESULTS: Overall, 111 specimens yielded a positive individually stained smear; of these, 100 (90.1%, 95%CI 83.0–95.0) were also culture-positive compared to 504/543 smear-positives after bulk staining (92.8%, 95%CI 90.6–95.0). The proportions of smear-positive, culture-negative and smear- and culture-positive specimens were respectively 1.8% vs. 2.2% and 90.1% vs. 92.8%, for individual and bulk staining (non-significant).

CONCLUSIONS: The risk of transferring AFB from positive to negative smears during bulk AFB staining is negligible, if it occurs at all. Bulk staining should not be discouraged, as even in low-income countries this method will save significant resources, particularly manpower, and improve staining results in laboratories with a high workload.
No References
No Citations
No Supplementary Data
No Data/Media
No Metrics

Keywords: cross-contamination; fluorescence; microscopy; staining; tuberculosis

Document Type: Regular Paper

Affiliations: 1: TB Reference Laboratory, Public Health Laboratory Services Branch, Centre for Health Protection, Department of Health, Hong Kong, China 2: Mycobacteriology Unit, Institute of Tropical Medicine, Antwerp, Belgium; and International Union Against Tuberculosis and Lung Disease, Paris, France

Publication date: 2009-09-01

More about this publication?
  • The International Journal of Tuberculosis and Lung Disease publishes articles on all aspects of lung health, including public health-related issues such as training programmes, cost-benefit analysis, legislation, epidemiology, intervention studies and health systems research. The IJTLD is dedicated to the continuing education of physicians and health personnel and the dissemination of information on tuberculosis and lung health world-wide.

    Certain IJTLD articles are selected for translation into French, Spanish, Chinese or Russian. They are available on the Union website

  • Editorial Board
  • Information for Authors
  • Subscribe to this Title
  • International Journal of Tuberculosis and Lung Disease
  • Public Health Action
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more