The stages of mitosis include interphase, prophase, metaphase, anaphase and telophase. When we view mitotic cells, we are generally interested in the metaphase mitotic cells. This is the only stage in the entire cell cycle in which the nuclear lamins and nuclear envelope are depolymerized and a major redistribution of nonchromosomal nuclear antigens occurs. Distinct differences in the staining characteristics of the metaphase mitotic cells can be observed with various autoimmmune sera.
When reading ANA results, it's important to be familiar with the different stages of mitosis. To be considered positive there must be a clearly discernible pattern staining the nucleus of the interphase cell. When a pattern is present in the nucleus of the interphase cell, then the metaphase mitotic cells are examined to assist in identifying the pattern(s).
If there is no staining in the nucleus of the cell but there is a discernible pattern in the cytoplasm of the cell, the sample is reported as ANA negative. However, the presence of a cytoplasmic pattern should be noted.