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Abnormal bleeding is sometimes observed in patients with immunoglobulin light chain (AL) amyloidosis. Although several theories have been proposed regarding the pathological causes of the bleeding tendency in AL amyloidosis, many lacked sufficient evidence and full consensus. We conducted a retrospective survey at a single institution to assess bleeding manifestations, methods for evaluating hematological abnormalities, and treatments for bleeding in patients with systemic AL amyloidosis over the past 13 years. The participants were 10 men and 14 women, aged 39-84 years (mean 65 years). The prevalence of bleeding was 29%. Prolonged prothrombin time (PT), elevated plasmin-α2-antiplasmin complex, and factor X deficiency were distinctive to the bleeding group. Two case studies showed that tranexamic acid was effective for treating this hematological condition. However, two patients with normal PT and activated partial thromboplastin time (APTT) also had a bleeding manifestation. The rates of administration of coagulation and fibrinolytic tests were relatively low in the non-bleeding group. Therefore, a close investigation concerning coagulation and fibrinolysis should be performed in every patient with AL amyloidosis regardless of the PT/APTT values. A more careful, comprehensive, and large-scale study is required to reinforce these findings.

Molecular makers such as thrombin-antithrombin complex (TAT), prothrombin fragment 1+2 (F1+2), soluble fibrin (SF), and D-dimer, are useful markers in the diagnosis and assessment of various thrombotic conditions. These markers are measured in plasma after blood sampling. Difficult blood sampling is known to falsely elevate plasma TAT levels. However, it is not known exactly why this occurs. In the present study, we examined how levels of molecular markers of haemostatic and fibrinolytic activation change under various sampling conditions using vacuum tube samples from healthy volunteers. When blood was sampled continuously by taking 10 consecutive vacuum tube samples following application of a tourniquet, blood sampling resulted in an accurate assessment of these molecular makers. When blood was sampled continuously by taking vacuum tube samples every one minute over a total of 9 minutes to investigate possible changes in the levels of the molecular markers over time, plasma levels of TAT, SF, and F1+2 gradually increased with time. Plasma levels of TAT, F1+2, and SF increased beyond the normal range over the course of nine minutes. When blood was sampled using three alternative methods, which varied in terms of the duration of needle puncture (sampling B), duration of tourniquet use (sampling C), or both (sampling A), plasma TAT and SF levels were significantly increased with all three methods, compared to control samples. Plasma F1+2 levels were significantly increased with sampling methods A and B, compared to control samples, but not with sampling method C. On the other hand, plasma D-dimer levels were not significantly altered by any of the sampling methods. In conclusion, the results suggest that molecular markers of haemostatic and fibrinolytic activation, except for D-dimer, may be affected by sampling method, particularly the duration of needle puncturing. Therefore, care needs to be taken when using TAT, F1+2, and SF levels to diagnose and estimate activation of the coagulation system.