There are several limitations of the Kinyoun-cold method. One limitation is that it may be less sensitive than the Ziehl-Neelsen method. Another limitation is that the smears may be too thick, which may cause it to not stain adequately.A smaller limitation is that methylene blue and the decolorizer should always be stored at room temperature and away from light to prevent degradation. They also have a shelf life of 52 weeks.