Undifferentiated Connective-Tissue Disease Workup

Updated: Jun 15, 2021
  • Author: Bernard Hildebrand, MD, MA; Chief Editor: Herbert S Diamond, MD  more...
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Laboratory Studies

Laboratory test screening is helpful to identify markers that may suggest autoimmune inflammatory disease. Routine screening tests for undifferentiated connective-tissue disease (UCTD) should include the following:

  • Complete blood count
  • Erythrocyte sedimentation rate (ESR)
  • C-reactive protein (CRP)
  • Urinalysis with microscopic analysis
  • Serum creatinine
  • Rheumatoid factor (RF)
  • Antinuclear antibodies (ANA): The American College of Rheumatology Antinuclear Antibody Task Force recommends ANA screening be performed using an immunofluorescence assay (IFA). [50] Any ANA detected by an enzyme immunoassay (EIA) or enzyme-linked immunosorbent assay (ELISA) should be confirmed with IFA testing. [51]

Other studies to consider on a case-by-case basis include the following:

  • Creatine kinase and aldolase
  • Complement components (C3, C4, CH50)
  • Thyroid-stimulating hormone
  • Anti–cyclic citrullinated peptide (CCP)
  • Anti-Ro/SSA
  • Anti-La/SSB
  • Anti-Smith
  • Anti-U1-RNP
  • Anti-Jo1
  • Anti-Mi2
  • Anti-Scl70 (topoisomerase antibody)
  • Anti-cardiolipins
  • Anti-beta-2 glycoprotein 1
  • Lupus anticoagulant
  • Anti-Ku
  • Rapid plasma reagin (RPR) 
  • Vitamin D  (25[OH]D 3)

Anti-U1-RNP and Anti-Ro/SSA antibodies represent the antinuclear specificities most frequently detected in UCTD. Anti-Ro/SSA immunoglobulin G (IgG) antibodies are very common in UCTD. [52] Vitamin D deficiency in patients with UCTD may play a role in progression to a defined CTD, or may be a consequence of the illness. [53, 32]


Imaging Studies

Chest radiography in patients with UCTD may be normal or may show signs of pleural effusion, pericardial effusion, enlarged cardiac silhouette, longstanding pulmonary hypertension, or interstitial lung disease. Features of interstitial pneumonia may overlap with diagnostic criteria for interstitial pneumonia with autoimmune features. [39]  Computed tomography (CT) of the chest, particularly high-resolution CT scanning, may better characterize pulmonary disease associated with CTD.

Salivary gland ultrasonography (SGUS) was found to have good sensitivity and high specificity in differentiating Sjögren syndrome (SS) from UCTD. In a study that included 55 patients with SS and 54 with UCTD, patients with SS showed a higher SGUS score than those with UCTD [mean 2.2  vs 0.2, P < 0.0001). An SGUS cut-off >2 showed a sensitivity of 65%, a specificity of 96%, a positive predictive value of 95%, and a negative predictive value of 73% for SS diagnosis. [54]


Other Tests

See the list below:

  • Pulmonary function studies, including spirometry, lung volumes, and carbon monoxide–diffusing capacity assists in identifying interstitial lung disease or reactive airway disease.

  • Electrocardiography may be useful in patients with cardiopulmonary signs and symptoms. Nonspecific ischemic changes, axis deviation, or findings consistent with chamber enlargement may direct further evaluation.

  • Echocardiography can best clarify chamber sizes and function, estimate physiologic pressures (including pulmonary arterial pressures), and identify or quantitate the size of a pericardial effusion.

  • The Schirmer test is a useful screen for dry eyes and may be used to detect decreased tearing associated with primary or secondary Sjögren syndrome. This test is very sensitive, but the results may be abnormal in patients taking anticholinergic medications.

  • Rose Bengal staining of the cornea can reveal keratitis associated with diminished tearing in Sjögren syndrome.

  • Nailfold capillary microscopy may be used to identify dilated tortuous capillary loops, irregular capillary loops, and areas of avascularity or "dropout" in patients with Raynaud phenomenon. [55] These findings indicate an underlying CTD, including UCTD. [56]