Test Id : SMAS
Smooth Muscle Antibody Screen, Serum
Useful For
Suggests clinical disorders or settings where the test may be helpful
Evaluation of patients with hepatitis of unknown origin associated with hypergammaglobulinemia and/or abnormal liver enzymes
Reflex Tests
Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial tests.
| Test Id | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| SMAT | Smooth Muscle Ab Titer, S | No | No |
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
If smooth muscle antibody (SMA) screen is positive, then the SMA titer will be performed at an additional charge.
Method Name
A short description of the method used to perform the test
Indirect Immunofluorescence
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
Actin
F-actin
Immunology Profile
SMA (Smooth Muscle Antibodies)
SMA, Anti
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
If smooth muscle antibody (SMA) screen is positive, then the SMA titer will be performed at an additional charge.
Specimen Type
Describes the specimen type validated for testing
Serum
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Specimen Volume: 0.8 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial
Forms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-General Request (T239)
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
0.4 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | OK |
| Heat-Treated | Reject |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 21 days | |
| Frozen | 21 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Evaluation of patients with hepatitis of unknown origin associated with hypergammaglobulinemia and/or abnormal liver enzymes
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
If smooth muscle antibody (SMA) screen is positive, then the SMA titer will be performed at an additional charge.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Autoimmune hepatitis (AIH) is a chronic disease resulting from immune-mediated liver injury with varied clinical manifestations.(1-2) The precise factors leading to disease initiation and perpetuation are unknown, but likely reflect a combination of genetic predisposition relating to defects in immunological control of autoreactivity, as well as environmental triggers, which precipitate a persistent breakdown in self-tolerance.(2) Initially, patients with AIH may be clinically asymptomatic, and are usually identified only through an incidental finding of abnormal liver function tests.(1-4) At a more advanced stage, patients may manifest with symptoms such as jaundice, pruritus, or ascites, which are secondary to the more extensive liver damage. As implied by the name, AIH has many characteristics of an autoimmune disease, including female predominance, hypergammaglobulinemia, association with specific HLA alleles, responsiveness to immunosuppression, and the presence of autoantibodies.(1-3)
The clinical features of AIH are nonspecific and can be seen in variety of liver diseases such as drug/alcohol-associated hepatitis, viral hepatitis, and primary sclerosing cholangitis. Therefore, the diagnosis can be challenging. A set of diagnostic criteria for AIH has been published and includes the presence of various autoantibodies, elevated total IgG, evidence of hepatitis on liver histology, and absence of viral markers.(1,3,4) Based on the specific autoantibodies present, AIH can be categorized in three categories.(4) The most prevalent is AIH type 1, linked to the presence of smooth muscle autoantibodies (SMA), antinuclear antibodies (ANA) and perinuclear anti-neutrophil cytoplasmic antibodies. SMA are generally identified by indirect immunofluorescence using a smooth muscle substrate. The antigen specificity of SMA in the context of AIH has been identified as filamentous-actin (F-actin).(3) The combination of autoantibody serology, specifically SMA and anti-F-actin antibodies with liver histology and thorough clinical evaluation are useful in the evaluation of patients with suspected autoimmune hepatitis. SMAs are detected in up to 85% of patients with AIH, either alone or in conjunction with ANA.(1,4,5) The SMA titer can also contribute to International Autoimmune Hepatitis Group diagnostic score in patients with a probable or definite diagnosis of AIH.(1,4,5) These antibodies have also been reported in 33% to 65% of cases of primary biliary cholangitis/AIH overlap syndrome (6), the concomitant presence of SMA and AMA being highly suggestive in this setting.
Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Negative
Reference values apply to all ages.
Interpretation
Provides information to assist in interpretation of the test results
Positivity for smooth muscle antibodies (SMA) may help support a diagnosis of autoimmune hepatitis (AIH) following exclusion of other causes of hepatitis.
A negative result for SMA does not exclude a diagnosis of AIH.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Serologic tests for autoantibodies, including smooth muscle antibodies (SMA), should not be relied upon exclusively to determine the etiology or prognosis of patients with liver disease.
A positive result for SMA may occur in patients who do not have autoimmune hepatitis. A negative result does not exclude a diagnosis of autoimmune hepatitis.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. European Association for the Study of the Liver. EASL clinical practice guidelines: autoimmune hepatitis. J Hepatol. 2015; 63(4):971-1004
2. Mieli-Vergani G, Vergani D, Czaja AJ, et al. Autoimmune hepatitis. Nat Rev Dis Primers. 2018;4:18017. Published 2018 Apr 12. doi:10.1038/nrdp.2018.17
3. Sebode M, Weiler-Normann C, Liwinski T, Schramm C. Autoantibodies in Autoimmune Liver Disease-Clinical and Diagnostic Relevance. Front Immunol. 2018;9:609. Published 2018 Mar 27. doi:10.3389/fimmu.2018.00609
4. Terziroli Beretta-Piccoli B, Mieli-Vergani G, Vergani D. Autoimmune Hepatitis: Serum Autoantibodies in Clinical Practice. Clin Rev Allergy Immunol. 2022;63(2):124-137. doi:10.1007/s12016-021-08888-9
5. Bogdanos DP, Invernizzi P, Mackay IR, Vergani D. Autoimmune liver serology: current diagnostic and clinical challenges. World J Gastroenterol 2008;14:3374-87.
6. Muratori P, Granito A, Pappas G, et al. The serological profile of the autoimmune hepatitis/primary biliary cirrhosis overlap syndrome. Am J Gastroenterol. 2009;104(6):1420-1425. doi:10.1038/ajg.2009.126
Method Description
Describes how the test is performed and provides a method-specific reference
Both 1:40 (initial screening) and 1:20 dilutions of the patient's serum are added to fresh tissue from mouse stomach/kidney and incubated; fluorescein-conjugated antiglobulin is then added. The slides are read with a fluorescence microscope.(Package insert: Kallestad Mouse Stomach/Kidney. Bio-Rad Laboratories, Inc; 06/2022)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Monday through Saturday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
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- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their account representative. For assistance, contact Customer Service.
Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
86015
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| SMAS | Smooth Muscle Ab Screen, S | 26971-2 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| 609515 | Smooth Muscle Ab Screen, S | 26971-2 |