Background: Coagulation and fibrinolytic systems have been implicated in the pathogenesis of sarcoidosis. D-dimer (DD), a fibrin breakdown product, can serve as a fibrinolytic activity marker.

Objectives:  Our aim in this study was to determine the correlation between DD levels and disease activity in sarcoidosis.

Material and Methods: We retrospectively analyzed 66 patients with newly diagnosed sarcoidosis between 2000-2022. DD levels measured during the initial diagnosis. Diagnosis was made based on typical clinic appearance and/or histological finding of noncaseating granuloma. DD levels were measured turbidimetrically. Serum DD levels >500 ng/ml was considered positive. Patients were also evaluated with radiologic stage and spirometry. ESR, CRP, and ACE levels were also measured.

Results: Of the 66 patients analyzed, 25 (37.8%) were DD (+). Radiology showed that six patients  (9%) had stage 0, 22 (33.4%) had stage I, 24 (36.3%) had stage II, 14 (21.2%) had stage III disease. None had stage IV disease. DD positivity was correlated with disease stage. Of the 22 stage I patients, 12 (54.5%) were DD (+) and of 24 stage II patients 8 (33.4%) were DD (+). Among DD (+) patients, stage I and stage II disease was more common (83%). Median DLco was also found to be significantly lower in DD (+) patients; 75.4% in DD (+) patients and 89.9% in DD (-) patients. Serum ACE levels were also higher in DD (+) patients with a median of 84.3 IU/L, and a median of 44.7 IU/L in DD (-) patients.

Conclusion: DD was frequently positive and DD positivity was found to be highly correlated with disease stage, lower DLco and elevated ACE levels. This implies that DD may be an useful marker for disease activity, but further studies are required.