The Antinuclear Antibody (ANA) test detects certain antibodies in the blood. Understanding results like “ANA Screen IFA w/Refl Titer and Pattern” can be complex. This article clarifies these technical terms.
The ANA Test and Initial Screening
Antinuclear Antibodies (ANAs) are autoantibodies produced by the immune system that mistakenly target components within the body’s own cell nuclei. While commonly associated with autoimmune diseases, ANAs can also be found in healthy individuals. The “ANA Screen” is the initial laboratory test to detect these autoantibodies.
The gold standard method for ANA testing is the Indirect Immunofluorescence Assay (IFA). In this method, a patient’s blood serum is applied to specialized HEp-2 cells. If ANAs are present, they bind to the nuclear components. A fluorescent anti-human antibody is then added, attaching to bound ANAs and causing them to glow under a fluorescent microscope. This identifies the presence of ANAs and their specific pattern.
Understanding Titer and Pattern
The “w/Refl” in an ANA test result indicates a “with reflex” protocol. If the initial ANA screen is positive, the laboratory automatically proceeds to determine the titer and pattern without a separate order.
“Titer” measures the concentration of ANAs in the blood, expressed as a dilution ratio (e.g., 1:80, 1:160, 1:320). A higher second number indicates a greater antibody concentration. While low titers (e.g., 1:40 or 1:80) can be observed in healthy individuals, higher titers (1:160 or greater) are generally more clinically significant and may suggest autoimmune activity.
The “pattern” refers to how fluorescent antibodies stain the cell nucleus during the IFA test, providing clues about targeted nuclear components. Different patterns associate with various autoimmune conditions. For example, a homogeneous pattern (uniform nuclear staining) is often seen in systemic lupus erythematosus (SLE) and drug-induced lupus. A speckled pattern (fine or coarse dots) is frequently associated with Sjögren’s syndrome, mixed connective tissue disease, and SLE.
A nucleolar pattern (only nucleoli stain) can be seen in systemic sclerosis (scleroderma). A centromere pattern (discrete dots on chromosomes) is strongly linked to limited systemic sclerosis (CREST syndrome). Cytoplasmic patterns, targeting structures outside the nucleus, can be associated with conditions like autoimmune liver diseases.
Interpreting Your ANA Results
A positive ANA result, even with a high titer and specific pattern, does not definitively diagnose an autoimmune disease. Up to 20% of healthy adults can have a positive ANA, with this percentage increasing in individuals over 65.
The ANA result must always be interpreted by a healthcare provider alongside symptoms, medical history, physical examination, and other laboratory tests. Low positive ANA titers can occur non-specifically due to various factors, including infections (Epstein-Barr virus, hepatitis, Lyme disease), certain cancers, or as a side effect of some medications (hydralazine, procainamide, minocycline).
Discuss your ANA test result with your healthcare provider. They will determine if further testing, such as specific antibody panels, or a referral to a specialist like a rheumatologist, is necessary. Self-diagnosis based solely on an ANA result is not appropriate, as it is only one piece of a larger diagnostic puzzle.