The big picture: The ANA (Antinuclear Antibody) Pattern refers to the appearance of stained cells under a microscope during an ANA test. Different patterns provide clues about which autoimmune diseases may be present. Common ANA patterns include homogeneous, speckled, nucleolar, centromere, and others. Each pattern can be associated with specific autoimmune conditions, making this test a useful diagnostic tool alongside other clinical and laboratory evaluations.

Role in autoimmune disease diagnosis: Identifying the ANA pattern helps clinicians refine their diagnosis of autoimmune diseases. While a positive ANA test indicates the presence of antibodies, the pattern can offer more insight into which specific condition might be involved. Combining the pattern with other laboratory findings and clinical symptoms allows for a more targeted diagnosis.

Differentiation between patterns: ANA patterns are categorized by anti-cell (AC) pattern codes from AC-1 to AC-28. Below are the most common types.

AC	Staining Pattern	Definition	Disease Associations
1	Homogeneous	Diffuse nuclear staining in resting cells and chromosome regions	SLE, Sjögren's syndrome, Systemic sclerosis, RA, Hashimoto's, Autoimmune hepatitis
2	Dense Fine Speckled	Speckles distributed throughout the nucleus, excluding nucleoli	Common in healthy individuals
3	Centromere	30-60 large speckles aligning with chromosomes	Limited Systemic Sclerosis, Primary Biliary Cholangitis, Sjögren's, Raynaud's
4	Fine Nuclear Speckled	Hundreds to thousands of fine dots throughout the nucleus	SLE, Subacute Cutaneous Lupus, Sjögren's, Systemic sclerosis, Dermatomyositis, RA
5	Coarse Nuclear Speckled	Larger nuclear dots than fine speckled pattern	SLE, Mixed Connective Tissue Disease (MCTD)
6	PML-Sp100 Nuclear Body	5-20 large speckles present in the nucleus	Primary Biliary Cholangitis
8-10	Nucleolar	Homogeneous or speckled staining of the nucleolus	Systemic sclerosis, SLE, Raynaud’s, Sjögren's, Polymyositis
19-20	Cytoplasmic Fine Speckled	Fine speckles distributed throughout the cytoplasm	Dermatomyositis, SLE, Sjögren’s, Polymyositis, Systemic sclerosis
21	Antimitochondrial (AMA)	Granular cytoplasmic staining	Primary Biliary Cholangitis, SLE, Autoimmune hepatitis
22	Golgi Apparatus	Irregular staining of cytoplasm near the nucleus	Viral infections, Sjögren's, SLE, RA