Article Text

Download PDFPDF

Not everything acid fast is Mycobacterium tuberculosis--a case report.
  1. E S Olson,
  2. A J Simpson,
  3. A J Norton,
  4. S S Das
  1. Department of Medical Microbiology, St Bartholomew's Hospital, London, UK.


    The Ziehl-Neelsen (ZN) stain is important in identifying organisms that are acid fast, principally Mycobacterium tuberculosis. However, decolorisation with a weaker acid concentration (for example 1% hydrochloric acid), often used in ZN staining in histology, can result in a wider variety of organisms appearing acid fast and can be a cause of misidentification. To illustrate this point, a patient is described with pulmonary nocardiosis who was misdiagnosed as having tuberculous empyema on pleural biopsy.

    Statistics from

    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.