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Updated: Apr 25, 2026

Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
Published on: September 9, 2012
Acquired factor X deficiency associated with atypical AL-amyloidosis
Masanori Furuhata1, Noriko Doki, Tsunekazu Hishima
1Hematology Division, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Japan.
Abstract:
We herein describe the case of a 77-year-old woman with acquired factor X deficiency that was likely caused by atypical amyloidosis. The patient developed severe gastrointestinal bleeding as a result of a significant decrease of factor X activity. Neither proteinuria nor diarrhea was observed as an initial manifestation. Although a bone marrow examination revealed direct fast scarlet-positive extracellular deposits, they did not exhibit red-to-green dichroism under polarized light. Immunofluorescence microscopy showed that the fibrillar proteins were positive for CD138 but negative for β2-microglobulin or amyloid A antibodies. These atypical pathological features of immunoglobulin light chain-amyloidosis in this patient might be related to its unique clinical presentation.
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