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Connective Tissue Diseases (CTDs)
CTDs are a group of closely related multisystem conditions.1 There are a number of different CTDs, including Sjögren’s syndrome, Systemic Lupus Erythematous (SLE) and Systemic Sclerosis (SSc) as well as several inflammatory muscle diseases and overlapping syndromes2 that are characterized by the presence of antinuclear antibodies (ANA) in a patient's blood. ANAs are a specific class of autoantibodies that have the capability of binding and destroying certain structures within the nuclease of a cell. These include antibodies against single and double-stranded DNA (dsDNA), and may also target other nuclear antigens also referred to as extractable nuclear antigens (ENA).
Classification Guidelines
According to the 2016 American College of Rheumatology/European League Against Rheumatism classification criteria for primary Sjögren's syndrome, individuals with signs and/or symptoms suggestive of Sjögren's syndrome who have a total score of ≥4 for the items below meet the criteria for primary Sjögren's syndrome:3
- Anti-SSA/Ro antibody positivity and focal lymphocytic sialadenitis with a focus score of ≥1 foci/4 mm2, each scoring 3;
- An abnormal Ocular Staining Score of ≥5 (or van Bijsterveld score of ≥4);
- A Schirmer's test result of ≤5 mm/5 min; and
- An unstimulated salivary flow rate of ≤0.1 mL/min, each scoring 1.
According to the 1997 Update of the 1982 American College of Rheumatology Revised Criteria for Diagnosis of SLE, 4 of 11 following criteria should be fulfilled at the same time or in succession:4
- Malar rash
- Discoid rash
- Photosensitivity
- Oral ulcers
- Non-erosive arthritis
- Pleuritis or pericarditis
- Renal disorder (proteinuria >0.5 g/day or cellular casts)
- Neurologic disorder
- Hematologic disorder
- Immunologic disorder (anti-DNA/anti-Sm/LE cell/false-positive STS
- A Positive ANA: An abnormal titre of antinuclear antibody by immunofluorescence OR an equivalent assay at any point in time and (in the absence of drugs)
According to the 2013 ACR/EULAR classification criteria for Systemic Sclerosis, patients with a total score of ≥9 are classified as having definite SSc.5
Items |
Sub-items |
Score |
| Skin thickening of the fingers of both hands extending proximal to the MCP joints (sufficient criteria) |
9 | |
Skin thickening of the fingers (only count the highest score) |
Puffy fingers Sclerodactyly of the fingers |
2 4 |
Fingertip lesions (only count the highest score) |
Digital tip ulcers Fingertip pitting scars |
2 3 |
| Telangiectasia |
2 | |
| Abnormal nail fold capillaries |
2 | |
Pulmonary arterial hypertension and/or interstitial lung disease (maximum score is 2) |
Pulmonary arterial hypertension Interstitial lung disease |
2 2 |
| Raynaud’s phenomenon |
3 | |
| SSc-related antibodies | Anti-centromere Anti- Scl-70 Anti-RNA polymerase III* |
3 |
According to the 2017 EULAR/ACR classification criteria for adult and juvenile Idiopathic Inflammatory Myopathies (IMM) and their major subgroups, including polymyositis/dermatomyositis, patients with probability above 55%, when no better explanation for the symptoms or signs exists, are classified as having IIM.6
Score points
Items |
No Biopsy |
Biopsy |
Age of onset of first related symptoms 18-40 age ≥40 age |
1.3 2.1 |
1.5 2.2 |
Muscle weakness
|
0.7 0.8 1.9 0.9 |
0.7 0.5 1.6 1.2 |
Skin manifestations
|
3.1 2.1 3.3 |
3.2 2.7 3.7 |
Other clinical manifestations
|
0.7 | 0.6 |
Laboratory measurements
|
3.9 1.3 |
3.8 1.4 |
Muscle biopsy features
|
1.7 1.2 1.9 3.1 |
Probability Calculation: 6
The criteria not including muscle biopsy data:
- Probability of IIM = 1/(1 + exponential function (6.49 − score))
The criteria including muscle biopsy data:
- Probability of IIM = 1/(1 + exponential function (5.33 − score))
Diagnosis and Test for Connective Tissue Diseases
The diverse and overlapping symptoms of connective tissue disease, particularly early in the course of the disease, can make diagnosis challenging. CTDs often present clinically with nonspecific, systemic symptoms, including arthritis, arthralgias, skin rashes, anemia, renal dysfunction, pleuritis, pericarditis. The diagnosis of a connective tissue disease is based on clinical signs and symptoms and characteristic imaging, histopathologic findings, and serologic testing results.1
Testing can help to:1
• Determine if referral to a specialist is appropriate
• Ensure effective and timely treatment
• Prevent organ damage and death
EliA Symphony7
Abbreviation: sy
EliA Symphony: a clinically relevant tool
Sample material: Serum, plasma (EDTA, citrate, heparin)
Reference Values
Measuring range: 0.03–32 ratio
| Value | Classification |
| <0.7 ratio | Negative |
| 0.7–1.0 ratio | Equivocal |
| >1.0 ratio | Positive |
EliA dsDNA8
Abbreviation: dn
EliA dsDNA is intended for the in vitro quantitative measurement of IgG antibodies directed to dsDNA in human serum and plasma as an aid in the clinical diagnosis of systemic lupus erythematosus (SLE).
Sample material: Serum, plasma (EDTA, citrate)
Reference Values
Measuring range: 0.5–379 IU/ml
| Value | Classification |
| <10 IU/ml | Negative |
| 10–15 IU/ml | Equivocal |
| >15 IU/ml | Positive |
EliA U1RNP9
Abbreviation: rn
EliA U1RNP is intended for the in vitro quantitative measurement of IgG antibodies directed to U1RNP in human serum and plasma as an aid in the clinical diagnosis of mixed connective tissue disease (MCTD) and systemic lupus erythematosus (SLE).
Sample material: Serum, plasma (EDTA, citrate)
Reference Values
Measuring range: 0.3–240 U/ml
| Value | Classification |
| <5 U/ml | Negative |
| 5–10 U/ml | Equivocal |
| >10 U/ml | Positive |
EliA RNP7010
Abbreviation: 70
EliA RNP70 is intended for the in vitro quantitative measurement of IgG antibodies directed to RNP70 in human serum and plasma as an aid in the clinical diagnosis of mixed connective tissue disease (MCTD) and systemic lupus erythematosus (SLE).
Sample material: Serum, plasma (EDTA, citrate)
Reference Values
Measuring range: 0.3–240 U/ml
| Value | Classification |
| <7 U/ml | Negative |
| 7–10 U/ml | Equivocal |
| >10 U/ml | Positive |
EliA SmDP 11
Abbreviation: smd
EliA SmDP is intended for the in vitro quantitative measurement of IgG antibodies directed to Sm in human serum and plasma as an aid in the clinical diagnosis of systemic lupus erythematosus (SLE).
Sample material: Serum, plasma (EDTA, citrate)
Reference Values
Measuring range: 0.6–480 U/ml
| Value | Classification |
| <7 U/ml | Negative |
| 7–10 U/ml | Equivocal |
| >10 U/ml | Positive |
EliA Ro12
Abbreviation: ro
EliA Ro is intended for the in vitro quantitative measurement of IgG antibodies directed to Ro in human serum and plasma as an aid in the clinical diagnosis of Sjögren's syndrome and systemic lupus erythematosus (SLE).
Sample material: Serum, plasma (EDTA, citrate)
Reference Values
Measuring range: 0.3–240 EliA U/ml
| Value | Classification |
| <7 U/ml | Negative |
| 7–10 U/ml | Equivocal |
| >10 U/ml | Positive |
EliA La13
Abbreviation: la
EliA La is intended for the in vitro quantitative measurement of IgG antibodies directed to La in human serum and plasma as an aid in the clinical diagnosis of Sjögren's syndrome and systemic lupus erythematosus (SLE).
Sample material: Serum, plasma (EDTA, citrate)
Reference Values
Measuring range: 0.4–282 U/ml
| Value | Classification |
| <7 U/ml | Negative |
| 7–10 U/ml | Equivocal |
| >10 U/ml | Positive |
EliA CENP14
Abbreviation: ce
EliA CENP is intended for the in vitro quantitative measurement of IgG antibodies directed to CENP in human serum and plasma as an aid in the clinical diagnosis of scleroderma (CREST Syndrome).
Sample material: Serum, plasma (EDTA, citrate)
Reference Values
Measuring range: 0.4–240 U/ml
| Value | Classification |
| <7 U/ml | Negative |
| 7–10 U/ml | Equivocal |
| >10 U/ml | Positive |
EliA Scl-70S 15
Abbreviation: scs
EliA Scl-70S is intended for the in vitro quantitative measurement of IgG antibodies directed to Scl-70 in human serum and plasma as an aid in the clinical diagnosis of scleroderma (diffuse form).
Sample material: Serum, plasma (EDTA, citrate)
Reference Values
Measuring range: 0.6–240 U/ml
| Value | Classification |
| <7 U/ml | Negative |
| 7–10 U/ml | Equivocal |
| >10 U/ml | Positive |
EliA Jo-116
Abbreviation: jo
EliA Jo-1 is intended for the in vitro quantitative measurement of IgG antibodies directed to Jo-1 in human serum and plasma as an aid in the clinical diagnosis of polymyositis/ dermatomyositis.
Sample material: Serum, plasma (EDTA, citrate)
Reference Values
Measuring range: 0.3–240 U/ml
| Value | Classification |
| <7 U/ml | Negative |
| 7–10 U/ml | Equivocal |
| >10 U/ml | Positive |
Reference values apply to all ages. Reference values, coating, dilution and sample material have been taken from respective Phadia™ 250 instrument Directions for Use. These data are intended as a guide and should be treated accordingly.
If you have any questions or uncertainty please contact us >
- Adebajo AO, Dickson DJ. Collected reports on the rheumatic diseases. Connective Tissues Disease and the Role of the General Practitioner. www.arthritisresearchuk.org/~/media/Files/Education/Hands-On/IP03-Sep-2000.ashx. Accessed November 2017.
- Gaubitz M. Epidemiology of connective tissue disorders. Rheumatology (Oxford). 2006;45(Suppl 3):iii3-4.
- Shiboski CH, Shiboski SC, Seror R, et al. 2016 American College of Rheumatology/European League Against Rheumatism Classification Criteria for Primary Sjogren’s Syndrome. Ann Rheum Dis. 2017;76(1):9-16.
- American College of Rheumatology. 1997 Update of the 1982 ACR Criteria for the Classification of SLE. http://www.rheumatology.org/Portals/0/Files/1997%20Update%20of%201982%20Revised.pdf. Accessed December 2017.
- van den Hoogen F. Classification Criteria for Systemic Sclerosis: An ACR-EULAR Collaborative Initiative. Arthritis Rheum. 2013; 65(11):2737-2747.
- Bottai M, Tjärnlund A, Santoni G, et al. EULAR/ACR Classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups: a methodology report. RMD Open. 2017;3:e000507.
- Phadia™ EliA™ Symphony Directions for Use for the Phadia 250 Laboratory System. Issued April 2017.
- EliA dsDNA Directions for Use for the Phadia 250 Laboratory System. Issued February 2017.
- EliA U1RNP Directions for Use for the Phadia 250 Laboratory System. Issued April 2017.
- EliA RNP70 Directions for Use for the Phadia 250 Laboratory System. Issued March 2017.
- EliA SmDp Directions for Use for the Phadia 250 Laboratory System. Issued June 2017.
- EliA Ro Directions for Use for the Phadia 250 Laboratory System. Issued March 2017.
- EliA La Directions for Use for the Phadia 250 Laboratory System. Issued March 2017.
- EliA CENP Directions for Use for the Phadia 250 Laboratory System. Issued April 2017.
- EliA Scl-70 Directions for Use for the Phadia 250 Laboratory System. Issued August 2016.
- EliA Jo-1 Directions for Use for the Phadia 250 Laboratory System. Issued March 2017.
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