<P> Studies have shown that an AFB stain without a culture has a poor negative predictive value . An AFB Culture should be performed along with an AFB stain; this has a much higher negative predictive value . </P> <P> Initially, Carbol Fuchsin stains every cell . When they are destained with acid - alcohol, only non-acid - fast bacteria get destained since they do not have a thick, waxy lipid layer like acid - fast bacteria . When counter stain is applied, non-acid - fast bacteria pick it up and become blue when viewed under the microscope . Acid - fast bacteria retain Carbol Fuchsin so they appear red . </P> <Ul> <Li> 1% sulfuric acid alcohol for actinomycetes, nocardia . </Li> <Li> 0.5--1% sulfuric acid alcohol for oocysts of isospora, cyclospora . </Li> <Li> 0.25--0.5% sulfuric acid alcohol for bacterial endospores . </Li> <Li> Brucella differential stain--glacial acetic acid used, no heat applied, secondary stain is loeffler's methylene blue . </Li> <Li> Kinyoun modification (or cold Ziehl--Neelsen technique) is also available . </Li> <Li> A protocol in which a detergent is substituted for the highly toxic phenol in the fuchsin staining solution . </Li> </Ul> <Li> 1% sulfuric acid alcohol for actinomycetes, nocardia . </Li>

What is the secondary stain in the acid fast stain