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Blood Test Tracker

Anti-SSB/La Antibody

Looks for antibodies to La (SSB), which often appear together with anti-Ro. They are linked to Sjögren's disease and lupus and matter for pregnancy planning.

AI-verified against cited sources. Awaiting expert reviewAlso called SSB, SS-B, Anti-LaLOINC 29965-1

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What it is

La, also called SSB, is a protein inside the nucleus of your cells. Anti-SSB/La antibodies are autoantibodies, which means your immune system makes antibodies against your own proteins. This test is usually ordered together with anti-SSA/Ro after a positive ANA, or when someone has dry eyes, dry mouth, or joint or skin symptoms. Labs report a number plus a call of negative, equivocal or positive. The cutoffs depend on the lab's test kit.

Why it matters

Anti-SSB/La is seen in about half of people with Sjögren's disease (also called Sjögren's syndrome) and in a smaller share of people with lupus or scleroderma. ARUP Laboratories notes it is more specific when no other extractable nuclear antigen (ENA) antibody is present. Unlike anti-SSA/Ro, it is not one of the items in the 2016 ACR/EULAR Sjögren classification criteria. Like anti-Ro, it can cross the placenta, so a positive result matters for pregnancy planning. Your clinician reads it with your symptoms and other antibody results.

If it’s high

A positive result means your blood has antibodies to La/SSB. They are most often seen in Sjögren's disease and lupus. A positive result by itself does not mean you have either one. It also matters for pregnancy, because the antibodies can reach the baby.

Common causes

  • Sjögren's disease (Sjögren's syndrome)
  • Lupus (systemic lupus erythematosus)
  • Systemic sclerosis (scleroderma), less often
  • No known condition: antibodies like these can be found in some healthy people

What can help

  • Ask your clinician how this result fits with symptoms such as dry eyes, dry mouth, joint pain or a rash
  • If you are pregnant or may become pregnant, tell your obstetric and rheumatology teams about this result so they can plan monitoring
  • Ask what your anti-SSA/Ro (Ro52 and Ro60) results were

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

For adults: 0–40 AU/mL. Source: ARUP Laboratories.

ARUP Laboratories interpretation (multiplex bead assay; lab-specific)

  • Negativebelow 30 AU/mL
  • Equivocal30 to under 41 AU/mL
  • Positive41 and above AU/mL

What can affect your result

  • Lab and test kit: units and cutoffs differ between labs, so compare results only from the same lab
  • Ancestry: in a New York City lupus registry, anti-SSB/La was most common in Asian patients and least common in White patients
  • Pregnancy: the antibodies can cross the placenta
  • Hemolyzed, severely lipemic or contaminated samples can be rejected or give unreliable results (ARUP specimen requirements).
  • Labs use different test kits, scales and cutoffs (for example AU/mL, antibody index or chemiluminescent units), so a number from one lab can't be compared with a number from another. Compare results from the same lab and test.

Not a short-term marker. These antibodies are usually checked to help sort out a condition, not to follow day-to-day changes.

When to talk to a clinician

A positive anti-SSB/La result is not an emergency by itself. Contact your clinician soon for dry eyes or mouth that affect eating or vision, swollen glands in the face or neck, joint swelling or a new rash. If you are pregnant, let your care team know about this result early. Call 911 or your local emergency number for severe chest pain, trouble breathing or fainting.

Questions you could ask

  • Why was the anti-SSB/La test ordered for me?
  • How does this result fit with my symptoms and my anti-SSA/Ro result?
  • Would it help to see a rheumatologist, a specialist in autoimmune conditions?
  • If I am pregnant or planning a pregnancy, does this result change how I am followed?

Questions people ask

Does a positive anti-SSB/La result mean I have Sjögren's disease?

Not by itself. The antibody is common in Sjögren's disease, but it also appears in lupus and other conditions, and sometimes in people with no known condition. Your clinician looks at your symptoms and other tests, including anti-SSA/Ro, before deciding what it means.

Why was I tested for SSB along with SSA?

The two antibodies often appear together and are usually ordered as a pair. Having both can change how your clinician reads the result and how a pregnancy is followed.

Show the science and sources

For clinicians and researchers

La/SSB is an RNA-binding nuclear protein. ARUP Laboratories states that anti-SSB is seen in 50 to 60% of Sjögren syndrome cases and is specific if it is the only ENA antibody present, and that 15 to 25% of patients with SLE and 5 to 10% of those with progressive systemic sclerosis also have it. ARUP reports it by a semi-quantitative multiplex bead assay in AU/mL (negative 29 or less, equivocal 30 to 40, positive 41 or more); other labs use other kits and units, so numbers are not interchangeable. The 2016 ACR/EULAR primary Sjögren criteria score anti-SSA/Ro (3 points) but not anti-SSB. Maternal anti-Ro with or without anti-La is linked to neonatal lupus: congenital complete heart block occurred in 1.6% of infants in a prospective cohort and in 1.9% of anti-Ro and/or anti-La-positive pregnancies in pooled prospective studies. The 2020 ACR reproductive health guideline has specific recommendations for patients positive for anti-Ro/SSA and/or anti-La/SSB.

LOINC 29965-1 (primary), 17791-5, 33613-1, 45142-7. Specimen: serum.

Sources

  1. SSB (La) (ENA) Antibody, IgG (test 0050692), ARUP Laboratories
  2. Extractable Nuclear Antigen Antibodies (SSA 52, SSA 60, and SSB) (test 0050791), ARUP Laboratories
  3. 2016 American College of Rheumatology/European League Against Rheumatism Classification Criteria for Primary Sjögren's Syndrome, Arthritis & Rheumatology (2017)
  4. Incidence and spectrum of neonatal lupus erythematosus: a prospective study of infants born to mothers with anti-Ro autoantibodies, The Journal of Pediatrics (2003)
  5. Autoimmune Congenital Complete Heart Block: How Late Can It Occur?, AJP Reports (2023)
  6. 2020 American College of Rheumatology Guideline for the Management of Reproductive Health in Rheumatic and Musculoskeletal Diseases, Arthritis & Rheumatology (2020)
  7. Sjögren's Disease: Diagnosis, Treatment, and Steps to Take, National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIH) (2024)
  8. Prevalence of concomitant rheumatologic diseases and autoantibody specificities among racial and ethnic groups in SLE patients, Frontiers in Epidemiology (2024)

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

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