Coagulation Test Correlates Protein Concentration for Plasma Cell Dyscrasia

Prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen activity have been linked with clinical history and disease parameters in patients with plasma cell dyscrasia.

Scientists at the University of Arkansas for Medical Sciences (Little Rock, AR, USA) studied coagulation tests in a total of 252 patients. Of these, 79 patients (31%) had abnormal routine screening coagulation test results. An isolated prolonged PT of greater than 15 seconds was found in 62 patients (25%), and 10 patients had prolonged PT and APTT (4%).

Prothrombin time, APTT, and fibrinogen activity were analyzed on the STA-R Evolution, using PT reagent Neoplastine CI PLUS and APTT reagent STA-PTT A, all products of Diagnostica Stago (Parsippany, NJ, USA). Fibrinogen activity was determined by measuring the clotting time of diluted plasma in the presence of excess thrombin with a reference range of 197–447 mg/dL. The quantitation of monoclonal proteins was performed by separating serum proteins using capillary electrophoresis with direct protein detection by UV absorbance at 200 nm.

An isolated prolonged PT was the most common abnormal coagulation test found in 25% of the patients. A prolonged PT was more frequently observed in 157patients with the multiple myeloma compared to the 34 monoclonal gammopathy of undetermined significance (MGUS) patients or other diagnostic categories of plasma cell dyscrasia. There were no differences immunoglobulin isotype in 62 patients with isolated prolonged PT compared to the 173 patients with normal screening coagulation tests. Fibrinogen activity was significantly lower in patients with prolonged PT although 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. Serum M protein concentrations were significantly elevated in patients with prolonged PT compared to patients with normal PT and were positively correlated with PT values.

The authors concluded that there was an association between disease severity and prolonged PT in 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. The study was published on December 7, 2012, in the International Journal of Laboratory Hematology.

Related Links:
University of Arkansas for Medical Sciences
Diagnostica Stago