Diagnostic Accuracy of Fat Pad Sampling and Bone Marrow Biopsy for AL Amyloidosis: A Systematic Review and Meta-Analysis

In this systematic review, we aimed to assess the diagnostic test accuracy (DTA) of abdominal fat pad sampling and bone marrow biopsy for immunoglobulin light-chain (AL) amyloidosis using organ biopsy as the reference standard. We searched the literature using PubMed, Embase, and CENTRAL databases from inception through March 2024. We used QUADAS-2 to assess the risk of bias and the GRADE approach to assess the certainty of evidence (COE). After deduplication, 29,237 records were screened, and 31 studies were included. Twenty-five studies (n=4,649) reported on fat pad sampling, with a pooled sensitivity of 0.77 (95%CI 0.72-0.81), while twenty studies (n=2,771) reported on bone marrow biopsy, with a pooled sensitivity of 0.55 (0.46-0.63). All studies enrolled patients with confirmed disease, specificity was not reported in the included studies. Fat pad aspiration (15 studies, n=1,590) and surgical or punch biopsy (4 studies, n=222) showed similar sensitivities of 0.80 (0.76-0.83) and 0.77 (0.61-0.88), respectively. In a single study (n=612), performing both tests together yielded a sensitivity of 0.89. COE was judged to be Moderate for fat pad sampling and Low for bone marrow biopsy.