Ziehl-Neelsen test /zēl″ nēl″sən/ [Franz Ziehl, German bacteriologist, 1857–1926; Friedrich K.A. Neelsen, German pathologist, 1854–1894] , one of the most widely used methods of acid-fast staining, commonly used in the microscopic examination of a smear of sputum suspected of containing Mycobacterium tuberculosis. See also acid-fast stain.
