A 28-year-old woman presents with dry cough and dyspnea. Chest radiograph shows bilateral hilar lymphadenopathy with reticulonodular infiltrates. Transbronchial biopsy shows noncaseating granulomas containing asteroid bodies. Which laboratory finding best supports this diagnosis?

• A Elevated serum angiotensin converting enzyme level with reduced CD4 to CD8 ratio in bronchoalveolar lavage fluid
• B Positive c-ANCA with elevated serum creatinine
• C Positive anti-GBM antibodies with hemoptysis
• D Elevated serum calcium with increased CD4 to CD8 ratio in bronchoalveolar lavage fluid ✓

Explanation

Sarcoidosis features noncaseating granulomas, bilateral hilar adenopathy, hypercalcemia driven by calcitriol production within granulomas, elevated ACE levels, and a high CD4 to CD8 ratio in BAL fluid reflecting the CD4 Th1 response. Option A is wrong because the BAL ratio is increased, not decreased. c-ANCA suggests granulomatosis with polyangiitis and anti-GBM antibodies suggest Goodpasture syndrome.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.