Antibody Test Helps Diagnose Thrombotic Thrombocytopenic Purpura

By LabMedica International staff writers
Posted on 31 Mar 2010
An assay has been launched that will help diagnose thrombotic thrombocytopenic purpura (TTP).

The new adamts13 antibody assay will aid in the diagnosis of TTP, a rare disease in which small blood clots form in blood vessels throughout the body. TTP is caused by a deficiency of the naturally occurring enzyme, adamts13. Lack of enzyme activity is usually the consequence of antibodies that either inhibit or remove adamts13 from circulation.

The addition of adamts13 antibody assay to Bloodcenter of Wisconsin's (Milwaukee, WI, USA) laboratory evaluations of TTP will result in increased specificity for diagnosis, identification of optimal therapies for TTP patients, and enhanced prognostic value for the likelihood of relapse.

Low levels of adamts13 in patients with acquired TTP appear to be caused by the presence of circulating antibodies to adamts13. In the laboratory, about 80% of these antibodies inhibit activity of adamts13, and other laboratory tests cannot detect the remaining 20% of clinically important antibodies. BloodCenter's new adamts13 Antibody assay enhances detection by revealing the presence of antibodies not detected by inhibition methods.

Completing a suite of laboratory-developed assays that already includes adamts13 activity and adamts13 inhibitor, the newest test enables clinicians to diagnosis TTP due to low levels of adamts13, a capability not yet available at other laboratories.

According to Ken Friedman, M.D., the medical director of BCW's hemostasis reference laboratory, "TTP is often difficult to diagnose because the clinical symptoms overlap with other thrombocytopenic conditions, such as hemolytic uremic syndrome and immune thrombocytopenic purpura. Our suite of adamts13 assays provides a complete laboratory picture and will aid clinicians in the differential diagnosis of TTP.”

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