Test Id : SCL70
Scl 70 Antibodies, IgG, Serum
Useful For
Suggests clinical disorders or settings where the test may be helpful
Evaluating patients with clinical features of systemic sclerosis and in the differential evaluation of individuals at-risk for connective tissue disease with Hep-2 substrate antinuclear antibody positive result, preferably using
antinuclear antibodies
Testing for Scl70 antibodies is not useful who test negative for antinuclear antibody using Hep-2 substrate by IFA.
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information see Connective Tissue Disease Cascade.
Method Name
A short description of the method used to perform the test
Multiplex Flow Immunoassay
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
Autoantibodies to Scl 70 Antigen
DNA Topoisomerase 1 Antibodies
Scl70
Scleroderma Antibodies (? FOR SPECIFIC TEST)
Topoisomerase 1 Antibodies
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information see Connective Tissue Disease Cascade.
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
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Special Instructions
Library of PDFs including pertinent information and forms related to the test
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
Evaluating patients with clinical features of systemic sclerosis and in the differential evaluation of individuals at-risk for connective tissue disease with Hep-2 substrate antinuclear antibody positive result, preferably using
antinuclear antibodies
Testing for Scl70 antibodies is not useful who test negative for antinuclear antibody using Hep-2 substrate by IFA.
Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
For more information see Connective Tissue Disease Cascade.
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Scl 70 (DNA topoisomerase 1) is an enzyme localized in both the cytoplasm and the nucleoli of the interphase cell that is an autoantibody target in patients with systemic sclerosis (SSc).(1,2) SSc is a complex autoimmune rheumatic disease of unknown etiology, characterized by widespread vasculopathy, fibrosis of the skin and internal organs, and immunologic derangements, including the production of diverse autoantibodies.(3-5) Antibody to Scl 70 is considered specific for SSc (also referred to as scleroderma) and together with anti-centromere and anti-RNA polymerase III autoantibodies is recommended for the diagnostic classification for disease by the American College of rheumatology/European League Against Rheumatism collaborative initiative.(3) Antibody to Scl 70 is typically associated with diffuse cutaneous SSc (dcSSc), a clinical subset of SSc which is characterized by disease severity including musculoskeletal and cardiac involvement, interstitial lung disease and poor survival outcomes.(4,5) In addition, Scl 70 antibody are more commonly found in African American patients with dcSSc compared to their Caucasian counterpart.(6,7)
In general, the presence of Scl 70 antibody is associated with a positive antinuclear antibody (ANA) when tested with the HEp-2 substrate using the indirect immunofluorescence assay (IFA).(1,2) ANA positivity with HEp-2 substrate IFA referred to as Scl-70 pattern is a composite of five cellular regions: nucleus, nucleolus and cytoplasm in interphase cells; nucleolar organizing region and chromosomes in mitotic cells.(2) Antibodies to Scl 70 were traditionally tested in clinical laboratories using immunodiffusion (ID), however, with increasing demands, methods for the detection and quantification of these autoantibodies have evolved to include diverse types of solid-phase immunoassays (SPAs) such as the line immunoblot, enzyme-linked immunosorbent assay, multiplex bead immunoassay, chemiluminescence immunoassay, and fluorescence enzyme immunoassay.(6-10) These SPAs have been reported to be less specific than the ID, especially in distinguishing SSc patients from those with other rheumatic diseases, though performance characteristics of individual assays may vary.(6-8). In a recent report, it was noted that discrepancy between anti-Scl-70 antibody assays can have relevant implications for clinical care and trial enrichment strategies for SSc patients with interstitial lung disease.(9)
Data from routine clinical practice do suggest that at diagnosis, positive results for Scl 70 antibody using SPAs must be interpreted in the appropriate clinical context taking into consideration the presence of a positive ANA test using the HEp-2 substrate by IFA, and/or the level of anti-Scl 70 antibody level.(6-8, 10) Low levels of anti-Scl 70 antibodies have been reported in non-SSc patients including those with SLE.(6, 8, 10) In SLE patients, it remains to be determined if this points to a unique subset of individuals or the phenomenon is due to cross-reactivity with dsDNA antibody.(10) Based on this observation, testing for dsDNA antibody may provide additional diagnostic clues, especially in the absence of the ID assay.(10)
For more information see Connective Tissue Disease Cascade.
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.
<1.0 U (negative
> or =1.0 U (positive
Reference values apply to all ages.
Interpretation
Provides information to assist in interpretation of the test results
A positive test result for Scl 70 antibodies may be consistent with a diagnosis of systemic sclerosis in the appropriate clinical context.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Low positive Scl 70 antibody results should be interpreted with a high degree of suspicion. These can be seen in a number of inflammatory conditions as well as other connective tissue diseases, especially systemic lupus erythematosus.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Dellavance A, Gallindo C, Soares MG, et al. Redefining the Scl-70 indirect immunofluorescence pattern: autoantibodies to DNA topoisomerase I yield a specific compound immunofluorescence pattern. Rheumatology(Oxford). 2009;48(6):632-637
2. Andrade LEC, Klotz W, Herold M, et al. International consensus on antinuclear antibody patterns: definition of the ac-29 pattern associated with antibodies to DNA topoisomerase I. Clin Chem Lab Med. 2018;56(10):1783-1788
3. van den Hoogen F, Khanna D, Fransen J, et al. 2013 classification criteria for systemic sclerosis: an American College of rheumatology/European League against rheumatism collaborative initiative. Ann Rheum Dis. 2013;72(11):1747-1755
4. Walker UA, Tyndall A, Czirják L,et al. Clinical risk assessment of organ manifestations in systemic sclerosis: a report from the EULAR Scleroderma Trials and Research group database. Ann Rheum Dis. 2007;66(6):754-763
5. Nihtyanova SI, Sari A, Harvey JC, et al. Using autoantibodies and cutaneous subset to develop outcome-based disease classification in systemic sclerosis. Arthritis Rheumatol. 2020;72(3):465-476
6. Nandiwada SL, Peterson LK, Mayes MD, et al. Ethnic differences in autoantibody diversity and hierarchy: More clues from a US cohort of patients with systemic sclerosis. J Rheumatol. 2016;43(10):1816-1824
7. Homer KL, Warren J, Karayev D, et al. Performance of anti-topoisomerase I antibody testing by multiple-bead, enzyme-linked immunosorbent assay and immunodiffusion in a university setting. J Clin Rheumatol. 2020;26(3):115-118
8. Lam BH, Assassi S, Charles J, et al. False positive anti-Topoisomerase I (Scl-70) antibody results in clinical practice: A case series from a scleroderma referral center. Semin Arthritis Rheum. 2022;56:152052
9. Jandali B, Salazar GA, Hudson M, et al. The Effect of anti-Scl-70 antibody determination method on its predictive significance for interstitial lung disease progression in systemic sclerosis. ACR Open Rheumatol. 2022;4(4):345-351
10. Mahler M, Silverman ED, Schulte-Pelkum J, Fritzler MJ. Anti-Scl-70 (topo-I) antibodies in SLE: Myth or reality? Autoimmun Rev. 2010 Sep;9(11):756-60.
Method Description
Describes how the test is performed and provides a method-specific reference
Recombinant Scl 70 antigen is bound to polystyrene microspheres, which are impregnated with fluorescent dyes to create a unique fluorescent signature. Scl 70 antibodies, if present in diluted serum, bind to the Scl 70 antigen on the microspheres. The microspheres are washed to remove extraneous serum proteins. Phycoerythrin -conjugated antihuman IgG antibody is then added to detect IgG anti-Scl 70 bound to the microspheres. The microspheres are washed to remove unbound conjugate, and bound conjugate is detected by laser photometry. A primary laser reveals the fluorescent signature of each microsphere to distinguish it from microspheres that are labeled with other antigens, and a secondary laser reveals the level of PE fluorescence associated with each microsphere. Results are calculated by comparing median fluorescence response for Scl 70 microspheres to a 4-point calibration curve.(Package insert: BioPlex 2200 ANA Screen. Bio-Rad Laboratories; 02/2019)
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 Friday, Sunday
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 :
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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.
CPT codes are provided by the performing laboratory.
86235
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 |
|---|---|---|
| SCL70 | Scl 70 Ab, IgG, S | 47322-3 |
| 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.
|
|---|---|---|
| SCL70 | Scl 70 Ab, IgG, S | 47322-3 |