Immunology

Anti-Sm (Smith) Antibody

Normal Range
Negative (<1.0 Index)
Sample Type
Standard
Fasting
No
Unit
Index

Anti-Sm is an autoantibody directed against core proteins of small nuclear ribonucleoproteins (snRNPs). It is considered highly specific (nearly 99%) for Systemic Lupus Erythematosus (SLE). Within an ANA Profile, its presence is a major ACR classification criterion for Lupus, even though it is only present in about 15-30% of SLE patients.

Check Your Result

Check Your Result

Interactive
Index

Enter your lab result to see where you stand compared to the standard reference range.

Why Context Matters

While highly specific, the test has low sensitivity. A negative result does not rule out Lupus. Results can also vary between different assay methods (ELISA vs. Multiplex).

Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.

Clinical References

Source-of-truth databases and clinical guidelines for Anti-Sm (Smith) Antibody:

Related Indicators

DR

Medically Reviewed by Dr. Binoy Babu, MBBS

Board Certified Doctor • 10+ Years Clinical Experience

Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.

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