Test Overview
Test Methodology

Indirect Fluorescent Antibody (IFA), Mouse stomach kidney substrate

Test Usage

Positive in 50-80% of patients with chronic active hepatitis. Titers are negative in extra hepatic biliary obstruction. Antismooth muscle antibodies (SMA) are also seen in acute viral hepatitis; low titers may be seen in primary biliary cirrhosis.

Reference Range *

Negative

Test Limitations

Presence of strong antinuclear antibody may interfere with the interpretation of smooth muscle antibody.

Test Details
Days Set Up
Tuesday, Friday
Analytic Time

8 hours

Soft Order Code
SM
MiChart Code
ANTI-SM
Synonyms
  • Antismooth Muscle Antibody
  • Liver Smooth Muscle Antibody
  • SM
  • Smooth Muscle Antibody
Laboratory
Chemical Pathology
Section
Immunopathology
Specimen Requirements
Collection Instructions

Collect specimen in SST tube. Centrifuge, aliquot serum into a plastic vial and refrigerate. Specimen aliquot should be frozen if it's not going to be received in Immunology within 3 days of collection.

Alternate Specimen
Red top tube.
Yellow Top Tube
Normal Volume
0.5 mL serum
Minimum Volume
0.2 mL serum
Additional Information

Smooth muscle antibody measurements are useful in confirming the diagnosis of chronic active hepatitis (CAH). Titers generally range from 1:80-1:320 and persist for years. In viral hepatitis the titers are below 1:80 and are transient. Low titers (1:20 to 1:40) are found in approximately 50% of patients with primary biliary cirrhosis. If another antibody including Parietal Cell Antibody, Mitochondrial Antibody, or Liver Kidney Microsomal Antibody is noted to be present during the performance of this test, the client will be notified via a footnote in the report. Please contact the MLabs Client Services Center to request the additional auto-antibody; there will be a separate charge for each auto-antibody test ordered.

Billing
CPT Code
86256
Fee Code
21928
LOINC
5358-7
NY State Approved
No