ArticleGhosh HK, Cobb M, Pacey DP, Conklin S.
Pathology. 1978 Jul;10(3):257-61.
In the original Petroff procedure sputum is digested with NaOH and the centrifuged deposit neutralized with HCl before culturing. A modification in which digestion is arrested by dilution with water and the sediment is seeded on buffered media is simpler, quicker, safer and in our hands seems to give a greater number of positive smears and cultures for mycobacteria with less overgrowth by contaminants. The usefulness of regular smear examinations for excluding tuberculosis in nonspecific chest complaints is questioned.