Prolonged prothrombin time correlates with serum monoclonal protein concentration in patients with plasma cell dyscrasia

Introduction: Abnormal screening coagulation tests are frequently observed in asymptomatic patients with multiple myeloma and other plasma cell neoplasms.

Methods: Prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen activity were correlated with clinical history and disease parameters in patients referred to the Myeloma Institute for Research and Therapy.

Results: An isolated prolonged PT was the most common abnormal coagulation test (25%). Prolonged PT was more frequently observed in patients with multiple myeloma (n = 157) compared to MGUS patients (n = 34) or other diagnostic categories of plasma cell dyscrasia. There were no differences in age, gender, previous chemotherapy, or immunoglobulin isotype in patients with isolated prolonged PT (n = 62) compared to those with normal screening coagulation tests (n = 173). Fibrinogen activity was significantly lower in patients with prolonged PT; however, there was no correlation between fibrinogen activity and PT. Serum M protein concentrations were significantly greater in patients with prolonged PT and were positively correlated with PT.

Conclusion: An association between disease severity and prolonged PT is suggested by our finding that patients with multiple myeloma were more likely to have prolonged PT than patients with other plasma cell neoplasms. Of the factors examined, the monoclonal protein level was significantly higher in patients with isolated prolonged PT and correlated with PT.