ASMA optimal range and reference range
Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026
Sera's bands for ASMA:
- Optimal 0 – 1:20 titer; sufficient 1:20 – 1:80 titer; out of range below 0 or above 1:80 titer.
Evidence grade: Established clinical threshold. A band edge that corresponds to a recognised diagnostic, risk or treatment threshold from a major clinical guideline or public-health body.
All units
| Unit | Optimal | Sufficient | Out of range |
|---|---|---|---|
| titer | 0 – 1:20 | 1:20 – 1:80 | below 0 or above 1:80 |
What the evidence says
Scored rather than diagnostic: the IAIHG simplified criteria count a titre from 1:40 as weak support for autoimmune hepatitis and from 1:80 as stronger, always alongside IgG, histology and exclusion of viral hepatitis. The bands follow the laboratory reading of the same test: below 1:20 is the reference interval, 1:20 to 1:80 is a weak positive worth repeating, and 1:160 or more is positive. Low titres occur in other liver disease and in health, so this marker means little away from raised transaminases.
Assay: Results differ meaningfully between platforms and methods. Compare against the interval printed by the issuing laboratory before acting on a borderline value.
Sources
- British Society of Gastroenterology guidelines for diagnosis and management of autoimmune hepatitis — Gleeson D, Bornand R, Brownlee A, et al. — Gut, 2025 · Clinical guidelineTable 6, the simplified diagnostic criteria adapted from Hennes: ANA or ASMA at a titre above 1:40 scores +1 and above 1:80 scores +2, alongside IgG, histology and absence of viral hepatitis. Supports the 1:40 and 1:80 steps behind Sera's bands. Full text read through the Europe PMC full-text service for PMC12421125.
- Smooth Muscle Antibody, IgG Titer — ARUP Laboratories, 2026 · Laboratory / reference-interval sourceReference interval less than 1:20; 1:20 to 1:80 is weak positive with a repeat suggested in two to three weeks; 1:160 or greater is positive and suggestive of autoimmune hepatitis. The same split as Sera's sufficient band of 20 to 80. Test directory page as opened in October 2026.
What Anti-Smooth Muscle Antibody (ASMA) measures
An antibody against smooth muscle actin, and with ANA one of the two markers of type 1 autoimmune hepatitis.
Ordered with ANA and AMA when transaminases are raised without an obvious cause. The international scoring criteria for autoimmune hepatitis count 1:40 as weak support and 1:80 or above as stronger, which is where Sera's bands come from. A low titre alone means little; the diagnosis rests on the antibodies, IgG, and biopsy together. Sera stores the dilution denominator, so a report reading 1:80 is entered as 80.