Laboratory testing in the evaluation of interstitial lung disease

Laboratory tests to order in the majority of patients with interstitial lung disease

Complete blood count and differential

Urinalysis

Alkaline phosphatase

Alanine aminotransferase (ALT, SGPT) and aspartate aminotransferase (AST, SGOT)

Blood urea nitrogen (BUN)

Creatinine

Tests for possible rheumatic disease

Antinuclear antibody (ANA)
Rheumatoid factor (RF)

Laboratory tests to order in selected patients with interstitial lung disease

Additional possible tests for systemic rheumatic disease*

Anti-cyclic citrullinated peptide (Anti-CCP)
Creatine kinase (CK), aldolase
Myositis-associated antibodies (eg, anti-tRNA synthetases Jo-1, PL-7, PL-12)
Anti-neutrophil cytoplasmic antibody (ANCA)
Anti-topoisomerase (Scl-70) antibody, anti-PM-1 (PM-Scl) antibody
Anti-double stranded (ds) DNA antibodies

Sicca features or positive anti-extractable nuclear antigen (ENA): Check anti-RO (SS-A), anti-La (SS-B), anti-ribonucleoprotein (RNP), serum protein electrophoresis, serum IgG4

Sclerodactyly, prominent GERD: Check anti-centromere, anti-topoisomerase I (anti-Scl-70)

Mechanics hands: Anti-tRNA synthetases (eg, Jo-1, PL-7, PL-12, and others)

Amyopathic dermatomyositis: Anti-melanoma differentiation-associated gene 5 (MDA-5)

Suspicion of heart failure or pulmonary hypertension: Brain natriuretic peptide (BNP) or N-terminal proBNP (NT-proBNP)

Anemia and/or hemoptysis: Coagulation studies, anti-glomerular basement membrane (GBM) antibodies, antiphospholipid antibodies, serum IgA endomysial or tissue transglutaminase antibodies in patients who may have idiopathic pulmonary hemosiderosis

Mediastinal lymphadenopathy: serum protein electrophoresis

Beryllium exposure: Peripheral blood beryllium lymphocyte proliferation test

Risk factors for HIV: HIV test

Testing for hypersensitivity pneumonitis antibodies based on patient exposures

Laboratory tests that are unlikely to be helpful in the diagnosis of interstitial lung disease

Angiotensin converting enzyme (ACE)

Erythrocyte sedimentation rate (ESR)^¶

C-reactive protein (CRP)^¶

GERD: gastroesophageal reflux disease; IgA: immunoglobulin A; IgG4: immunoglobulin G4.
* Additional tests are obtained when rheumatic disease is suspected based on clinical features, positive antinuclear antibody (ANA) test, positive rheumatoid factor (RF), or presence of pleural disease on chest imaging.
¶ These tests are nonspecific. Occasionally, patients will have elevated values for ESR or CRP that are twice normal in the setting of an idiopathic interstitial pneumonia (IIP). So, these tests may be obtained to assess for undifferentiated rheumatic disease in a patient with IIP.

Graphic 105280 Version 3.0

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Laboratory testing in the evaluation of interstitial lung disease