Introduction:

All ANA tests must be performed on diluted serum so as to dilute out lots of nonspecific "reactivity" (standard is a 1:10 dilution of serum). The classical "ANA" is a fluorescent auto-immune antibody (Ab) screening test visually performed using a fluorescent microscope (so, sometimes called F-ANA) and is an "intellect intensive" test. F-ANA usually looks for ANAs in the IgG class (not in IgA or IgM). The substrate which provides the nuclei is either made of histological sections of tissue (cross-sections of nuclei) or cell culture monolayer sheets which have whole nuclei (such as HEp-2). Depending on source or method of substrate production, cells may contain typical or scant amounts of the various antigens. [ANA] [autoimmune] [muscle Bx & comprehensive muscle lab & path link]

Many labs use the automated, more "chemical", non-visual (ELISA) test methods for ANA, and such methods do not reveal visual patterns. 

Interpretation conventions or cautions:

When  a screening ANA by any method is positive, it ought to be considered a non-specific positive (viral infections and some other non-auto-immune disorders can cause positivity). Of the many possible types of autoantibodies, this ANA group of antibodies attaches to components of cell nuclei. The positive ANAs which also have "specificity" for DNA (non-soluble) or various ENAs (soluble, extractible nuclear [protein] antigens] are the ones more likely to herald or be associated with "lupus" or other disease listed below). "Negative"...not necessarily meaning the patient is negative for autoimmune disease...is failure of the test to react positively (non-reactive [NR]) at a standard 1:10 dilution of serum. [autoimmune disease]

Our LML uses an indirect fluorescent test (F-ANA) in which patient's antibody-containing serum is mixed with a human HEp-2 nucleus-containing substrate [ warning]. A variety of possible positive HEp2 nuclear staining patterns⁴ can be visualized with the fluorescent microscope, their specificities & significance^4,5 noted in this table:

References:

1. Interpretation of Diagnostic Tests, Wallach, 2000, 7th Ed.
2. James J, et. al., NEJM, 2004.
3. Judith James, MD, Oklahoma City, e-mail to JBC 15 Oct. 2004 (and the 11/04 LMC Lab issue of NewsPath.
4. Bradwell AR, et. al., Atlas of HEp-2 Patterns, 118 pages, 1995 (LML).
5. McCarty GA, Valencia DW, Fritzer MJ, Antinuclear Antibodies: Contemporary Techniques & Clinical Application to Connective Tissue Disease, 1984, 95 pages (JBC).