Test Catalog

Test Id : SP100

SP100 Antibody, IgG, Serum

Useful For
Suggests clinical disorders or settings where the test may be helpful

Evaluating the risk of primary biliary cholangitis in anti-mitochondrial antibody (AMA) negative patients by identification of Sp100 antibodies


Estimating risk in AMA-positive patients with incomplete feature of disease

Method Name
A short description of the method used to perform the test

Enzyme-Linked Immunosorbent Assay (ELISA)

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

SP100 Antibody, IgG, S

Lists additional common names for a test, as an aid in searching

Anti-sp100 Antibody

Primary Biliary Cirrhosis

Primary Biliary Cholangitis

Cholestatic Liver Disease

Specimen Type
Describes the specimen type validated for testing


Additional Testing Requirements

This is a first line test when primary biliary cholangitis is strongly suspected. It should be ordered in conjunction with AMA / Mitochondrial Antibodies (M2), Serum and GP210 / GP210 Antibody, IgG, Serum.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request (T728) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.4 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK
Heat-treated specimens 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

Evaluating the risk of primary biliary cholangitis in anti-mitochondrial antibody (AMA) negative patients by identification of Sp100 antibodies


Estimating risk in AMA-positive patients with incomplete feature of disease

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Primary biliary cholangitis (PBC) is a chronic and progressive autoimmune liver disease characterized by the destruction of the small intrahepatic bile ducts and a variable clinical course, which may include fatigue and pruritus. Untreated patients with PBC have a high risk of liver cirrhosis and related complications, liver failure and death.(1,2) The serological hallmark of PBC is the presence of anti-mitochondrial antibody (AMA) characterized by cytoplasmic reticular/AMA (anti-cell 21 [AC-21] based on the International Consensus on Antinuclear Antibody Patterns [ICAP] nomenclature) staining pattern on HEp-2 substrate by indirect immunofluorescence assay (IFA).(3) In addition, autoantibodies associated with the HEp-2 IFA nuclear patterns have been reported in a subset of patients with PBC who are seronegative for AMA or may be positive for AMA but have uncertain clinical or phenotypic attributes.(1,2,4,5) The HEp-2 IFA nuclear patterns in PBC include multiple nuclear dots (MND or AC-6) and punctate nuclear envelope (AC-12), which are associated with anti-Sp100 and anti-gp210 antibodies, respectively.(3) The diagnosis of PBC can be established if two out of the three following criteria are met: sustained elevated levels of alkaline phosphatase (ALP), evidence AMA or specific antinuclear antibody (ANA) (anti-Sp100 and anti-gp210 antibodies) and diagnostic liver histology.(2) Based on these criteria, a biopsy can be avoided in case of high ALP levels and detection of these PBC-specific autoantibodies.(1,2) Therefore, reliable and accurate serologic determination of PBC-specific autoantibodies play a critical role in disease evaluation.


Of the PBC-specific antibodies, the AMA is the most common, with the M2-type AMA (AMA-M2) the dominant target of the 9 subunits of the mitochondrial antigenic complex.(1,2) AMA-M2 target components of the 2-oxo-acid dehydrogenase complex: pyruvate dehydrogenase complex (PDC), 2-oxoglutarate dehydrogenase complex (OGDC), and branched-chain 2-oxoacid dehydrogenase complex (BCOADC). Specifically, autoantibodies mainly recognize the E2 subunits of these complexes: PDC-E2 (80%-90% of cases), BCOADC-E2 (50%-80% of cases) and OGDC-E2 (20%-60% of cases) and, to a lesser extent, the E1 and E3 subunits.(2). In addition to the diagnostic relevance of anti-gp210 IgG antibody, a few studies have suggested a role for their use in the risk stratification and prognosis in PBC; however, the significance of these remain contentious. In one study, the presence of anti-gp210 antibodies was reported to pose a significant risk for hepatic failure type progression, more severe interface hepatitis, and lobular inflammation compared to those with centromere antibodies who had relatively higher ductular reaction.(6) In other investigations, anti-gp210 and/or anti-Sp100 antibodies were reported to be useful in confirming a diagnosis of PBC or predicting development of disease in the context of AMA positivity in nonestablished PBC cases.(5,7)


The anti-Sp100 and anti-gp210 antibodies can also be determined using analyte-specific enzyme-linked immunosorbent assay, line blot immunoassay, and dot immunoassay.(4-8) In addition to the solid-phase immunoassays (SPA) for detecting antibodies to AMA, Sp100 and gp210, the use HEp-2 substrate by IFA provides a simple and strategic approach for confirming the presence of AMA cytoplasmic staining if positive by enzyme immunoassay (EIA) with the possibility of identifying patients who may be AMA-negative but positive to nuclear antibodies. In PBC patients, the nuclear envelope pattern is associated with anti-gp210 antibody, while the multiple nuclear dots pattern is specific for anti-Sp100 antibodies. However, expression of the multiple nuclear dot and the nuclear envelope patterns may not be easily identified in the presence of other antibodies. Testing for these antibodies is indicated in patients who are AMA positive by EIA as well as patients at-risk for PBC but are AMA negative. In addition to providing additional support for PBC diagnosis in AMA-positive and AMA-negative patients, the use of HEp-2 substrate offers the possibility to identify patients at-risk for PBC who may present with coexisting systemic autoimmune rheumatic diseases (systemic lupus erythematosus, systemic sclerosis, and Sjogren syndrome) or autoimmune liver disease (autoimmune hepatitis) through additional pattern recognition.(9,10) The use of SPA for ANA testing do not provide these additional diagnostic insights.

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: < or =20.0 Units

Equivocal: 20.1-24.9 Units

Positive: > or =25.0 Units

Provides information to assist in interpretation of the test results

A positive result for anti-Sp100 antibodies in the setting of chronic cholestasis after exclusion of other causes of liver disease is highly suggestive of primary biliary cholangitis.

Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Serologic tests for autoantibodies, including anti-Sp100, should not be relied upon exclusively to determine the etiology or prognosis of patients with primary biliary cholangitis (PBC).


A negative result for anti-Sp100 antibodies does not exclude a diagnosis of PBC.


Results of this assay should be used in conjunction with clinical findings and other serological tests.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Younossi ZM, Bernstein D, Shiffman ML, et al. Diagnosis and management of primary biliary cholangitis. Am J Gastroenterol. 2019;114(1):48-63

2. Lindor KD, Bowlus CL, Boyer J, Levy C, Mayo M. Primary biliary cholangitis: 2018 practice guidance update from the American Association for the Study of Liver Diseases. Hepatology. 2019;69(1):394-419

3. International Consensus on ANA Patterns. AC-20 Cytoplasmic fine speckled. ICAP; 2015. Accessed August 18, 2023. Available at www.anapatterns.org/view_pattern.php?pattern=20

4. Zhang Q, Liu Z, Wu S, et al. Meta-analysis of antinuclear antibodies in the diagnosis of antimitochondrial antibody-negative primary biliary cholangitis. Gastroenterol Res Pract. 2019;2019:8959103

5. Dahlqvist G, Gaouar F, Carrat F, et al. Large-scale characterization study of patients with antimitochondrial antibodies but nonestablished primary biliary cholangitis. Hepatology. 2017;65(1):152-163

6. Nakamura M, Kondo H, Mori T, et al. Anti-gp210 and anti-centromere antibodies are different risk factors for the progression of primary biliary cirrhosis. Hepatology. 2007;45(1):118-127

7. Jaskowski TD, Nandakumar V, Novis CL, Palmer M, Tebo AE. Presence of anti-gp210 or anti-sp100 antibodies in AMA-positive patients may help support a diagnosis of primary biliary cholangitis. Clin Chim Acta. 2023;540:117219

8. Munoz-Sanchez G, Perez-Isidro A, Ortiz de Landazuri I, et al. Working algorithms and detection methods of autoantibodies in autoimmune liver disease: A nationwide study. Diagnostics (Basel). 2022;12:697

9. Favoino E, Grapsi E, Barbuti G, et al. Systemic sclerosis and primary biliary cholangitis share an antibody population with identical specificity. Clin Exp Immunol. 2023;212(1):32-38

10. Wei Q, Jiang Y, Xie J, et al. Investigation and analysis of HEp 2 indirect immunofluorescence titers and patterns in various liver diseases [published correction appears in Clin Rheumatol. 2021 Apr;40(4):1667]. Clin Rheumatol. 2020;39(8):2425-2432. doi:10.1007/s10067-020-04950-7

Method Description
Describes how the test is performed and provides a method-specific reference

This test is intended for the semi-quantitative detection of anti-Sp100 antibody of the IgG class in human serum. A purified peptide corresponding to a portion of the Sp100 protein is bound to the wells of a polystyrene microwell plate. Pre-diluted controls and diluted patient sera are added to separate wells, allowing any Sp100 antibodies present to bind to the immobilized antigen. Unbound sample is washed away, and an enzyme labeled anti-human IgG conjugate is added to each well. A second incubation allows the enzyme labeled anti-human IgG to bind to any patient antibodies, which have become attached to the microwells. After washing away any unbound enzyme labeled anti-human IgG, the remaining enzyme activity is measured by adding a chromogenic substrate and measuring the intensity of the color that develops. The assay can be evaluated spectrophotometrically by measuring and comparing the color intensity that develops in the patient wells with the control in the control wells.(Package insert: QUANTA Lite sp100 ELISA 708990. INOVA Diagnostics; Rev. 3, 12/2018)

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.


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.

2 to 8 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

14 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


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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 has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

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.


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
SP100 SP100 Antibody, IgG, S 96565-7
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.
SP100 SP100 Antibody, IgG, S 96565-7

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | PHP Pdf | CMS Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports