Sign in →

Test ID: CTDC Connective Tissue Diseases Cascade, Serum

Reporting Name

Connective Tissue Disease Cascade,S

Useful For

Evaluation of patients with signs and symptoms compatible with connective tissue diseases


Initial evaluation of patients in clinical situations in which the prevalence of disease is low (6)


This test is not recommended for:

-Testing in clinical situations in which there is a high prevalence of connective tissue diseases (eg, rheumatology specialty practice)

-Follow-up evaluation of patients with known connective tissue diseases

Clinical Information

The following diseases are often referred to as connective tissue diseases (CTD): rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis including CREST syndrome (calcinosis, Raynaud phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia), Sjogren syndrome, mixed connective tissue disease, and idiopathic inflammatory myopathies. CTD (also known as systemic rheumatic diseases) are characterized by immune-mediated inflammation that involves the joints, skin, and visceral organs. These diseases are also accompanied by antibodies to a host of nuclear and cytoplasmic autoantigens.


The diagnosis of any CTD is based on clinical signs and symptoms and characteristic radiographic, histopathologic, and serologic findings. Certain CTD are characterized by autoantibodies that are highly specific for individual diseases as outlined in the Table. CTD often present clinically with signs and symptoms that are nonspecific, including constitutional signs such as fever, weight loss, fatigue, and arthralgias.


Table. Autoantibodies and Clinical Associations with Specific Connective Tissue Diseases

Cyclic citrullinated peptide antibodies

Rheumatoid arthritis

Double-Stranded DNA (dsDNA)

Systemic lupus erythematosus (SLE)

Smith (Sm)


Ribosome P



Sjogren syndrome (SjS)

SS-A/Ro (Ro52 or Ro60)

SjS, SLE, systemic sclerosis (SSc), antisynthetase syndrome

RNP 68 and A (RNP)

Mixed connective tissue disease

Topoisomerase 1 (topo-1, Scl-70)


Histidyl tRNA synthetase (JO1)

Idiopathic inflammatory myositis (commonly anti-synthetase syndrome)

Centromere B

SSc (most commonly the limited cutaneous forms: LcSSc)


In this testing cascade, serum is tested initially for the presence of antinuclear antibodies (ANA) and for cyclic citrullinated peptide (CCP) antibodies. The presence of CCP antibodies indicates a strong likelihood of rheumatoid arthritis (RA).(1) However, additional testing for rheumatoid factor, which is not included in the cascade, is important for optimal diagnosis as per the 2010 American College of Rheumatology/European League Against Rheumatism RA classification criteria.(2) The presence of ANA supports the possibility of a CTD, and the level of ANA is used to identify sera for second-order testing for antibodies to dsDNA and the other autoantigens. The decision threshold for performing second-order tests is based on empirical data derived from testing patients with varying levels of ANA and is chosen to minimize testing in situations in which positive results for dsDNA and other antibodies is very unlikely.(3) However, a negative ANA enzyme immunoassay result does not rule out a diagnosis of CTD as has been reported in a number of studies. Therefore, in patients with a strong clinical suspicion of CTD, testing for ANA by indirect immunofluorescence assay may be warranted.(4,5)


Interpretive comments are provided.


See individual test IDs for additional information.


Differential testing for Ro52 and Ro60 antibodies in SS-A/Ro positive patients may be useful in the diagnosis of specific CTD clinical subset, disease stratification, and prognosis. Consider testing for Ro52 and Ro60 antibodies (ROPAN / Ro52 and Ro60 Antibodies, IgG, Serum) if the patient is positive for SS-A/Ro.

Profile Information

Test ID Reporting Name Available Separately Always Performed
ANA2 Antinuclear Ab, S Yes Yes
CCP Cyclic Citrullinated Peptide Ab, S Yes Yes
IM_01 Interpretation No Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CMA Centromere Ab, IgG, S Yes No
CASMT ANA2 Cascade No No
RIB Ribosome P Ab, IgG, S Yes No
ENAE Ab to Extractable Nuclear Ag Eval,S Yes No
ADNAR dsDNA Ab with Reflex, IgG, S Yes No

Testing Algorithm

If antinuclear antibodies are greater than or equal to 3.0 U, then antibodies to double-stranded DNA (dsDNA), extractable nuclear antigen evaluation, ribosome P, and centromere are performed at an additional charge.


If result from dsDNA test is borderline, then dsDNA antibody by the Crithidia immunofluorescence assay will be performed at an additional charge.


For more information see Connective Tissue Disease Cascade.

Report Available

3 to 4 days

Day(s) Performed

Monday through Saturday

Clinical Reference

1. Tomar R, Homburger H: Assessment of immunoglobulins and antibodies. In: Rich R, Fleisher T, Shearer W, et al, eds. Clinical Immunology: Principles and Practice. 2nd ed. Mosby-Year Book Inc; 2001:120.1-120.14

2. Aletaha D, Neogi T, Silman AJ, et al: 2010 Rheumatoid arthritis classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Arthritis Rheum. 2010 Sep;62(9):2569-2581

3. Deng X, Peters B, Ettore MW, et al: Utility of antinuclear antibody screening by various methods in a clinical laboratory patient cohort. J Appl Lab Med. 2016 Jul 1;1(1):36-46

4. Pisetky DS, Spencer DM, Lipsky PE, Rovin BH: Assay variation in the detection of antinuclear antibodies in the sera of patients with established SLE. Ann Rheum Dis. 2018 Jun;77(6):911-913

5. Claessens J, Belmondo T, De Langhe E, et al: Solid phase assays versus automated indirect immunofluorescence for detection of antinuclear antibodies. Autoimmun Rev. 2018 Jun;17(6):533-540

6. van Boekel MAM, Vossenaar ER, van den Hoogen FHJ, van Venrooij WJ: Autoantibody systems in rheumatoid arthritis: specificity, sensitivity and diagnostic value. Arthritis Res. 2002;4(2):87-93

7. Kavanaugh A, Tomar R, Reveille J, Solomon DH, Homburger HA: Guidelines for clinical use of the antinuclear antibody test and tests for specific autoantibodies to nuclear antigens. Arch Pathol Lab Med. 2000 Jan;124(1):71-81

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)

Specimen Type


Specimen Required

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Information: Centrifuge and aliquot serum into plastic vial.

Specimen Minimum Volume

0.7 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 21 days
  Frozen  21 days

Special Instructions

Reference Values


≤1.0 U (negative)

1.1-2.9 U (weakly positive)

3.0-5.9 U (positive)

≥6.0 U (strongly positive)

Reference values apply to all ages.



<20.0 U (negative)

20.0-39.9 U (weak positive)

40.0-59.9 U (positive)

≥60.0 U (strong positive) 

Reference values apply to all ages.

Test Classification

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



83516-Centromere (if appropriate)

83516-Ribosome (if appropriate)

86225-ds-DNA Ab with Reflex (if appropriate)

86255-ds-DNA Ab by Crithidia IFA (if appropriate)

86235 x 6-RNP, Sm, SS-B, SS-A, Jo 1, and Scl 70 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CTDC Connective Tissue Disease Cascade,S 95267-1


Result ID Test Result Name Result LOINC Value
ANA2 Antinuclear Ab, S 94875-2
CCP Cyclic Citrullinated Peptide Ab, S 33935-8
IM_01 Interpretation 69048-7
Mayo Clinic Laboratories | Neurology Catalog Additional Information:

mml-Behavioral, mml-Cerebrovascular, mml-Epilepsy, mml-Headache, mml-Movement-Disorders, mml-Demyelinating-Diseases, mml-Neuroimmunology, mml-Neuromuscular, mml-Autonomic, mml-Pediatric, mml-Spinal-Cord, mml-Neuro-ophthalmology