Diagnostic value of bone marrow smear for amyloid detection and its correlation with clinical features in systemic light-chain amyloidosis

This study aimed to evaluate the diagnostic value of bone marrow smear in systemic light chain (AL) amyloidosis and to investigate the correlation between bone marrow amyloid deposition and clinical characteristics. A total of 252 patients with AL amyloidosis were enrolled, including 126 with positive bone marrow biopsies and 126 with negative biopsies. Bone marrow smear detected amyloid deposits in 121 of 252 patients (48.0%). Among the 126 patients with positive bone marrow biopsies, 121 (96.0%) had positive smears; among the 126 patients with negative biopsies, all 126 (100%) had negative smears. The overall concordance between smear and biopsy was 98.0% (247/252). In the AL group without concomitant plasma cell or B-cell disorders, bone marrow amyloid deposition was significantly associated with λ light chain type, lower hemoglobin levels, and elevated levels of ALP, GGT, β2-MG, and NT-proBNP, suggesting a correlation with impaired liver, kidney, and cardiac function. Survival analysis indicated that bone marrow amyloid deposition had no significant impact on prognosis. Bone marrow smear may serve as a rapid screening tool for AL amyloidosis, and its combination with biopsy could enhance diagnostic efficiency.