The FDA has approved MP Diagnostics HTLV Blot 2.4, the first FDA-licensed supplemental test for Human T-cell Lymphotropic Virus-I/II (HTLV-I/II). This test is intended for use as an additional, more specific test for human serum or plasma specimens that have previously tested positive on an FDA-licensed HTLV-I/II blood donor screening test. The MP Diagnostics HTLV Blot 2.4 is a qualitative enzyme immunoassay test intended to confirm infection with HTLV and to differentiate between HTLV-I and HTLV-II.

The Human T-cell Lymphotropic viruses (HTLV) are a group of human retroviruses known to cause diseases such as adult T-cell leukemia/lymphoma (a rare form of blood cancer) and inflammation of the nerves in the spinal cord (myelopathy), as well as other conditions. HTLV can be transmitted from person to person through breastfeeding, unprotected sexual contact, or transfusion of blood from an infected donor.

Because HTLV can be transmitted through blood, the FDA requires that donated blood be tested for HTLV-I/II antibodies. Currently there are two FDA-licensed screening tests for HTLV-I/II. If the test is positive, the donation is discarded and the donor is notified of his or her deferral. The MP Diagnostics HTLV Blot 2.4 provides blood establishments with additional information to convey to the donor; specifically, the test can confirm HTLV infection and determine which virus type is causing the infection, HTLV-I or HTLV-II.

“The approval of MP Diagnostics HTLV Blot 2.4 will help blood establishments better counsel donors who have had positive results on an FDA-licensed HTLV-I/II screening test,” said Karen Midthun, M.D., director of FDA’s Center for Biologics Evaluation and Research.

Many people who are infected with HTLV are unaware of the infection because the virus may not cause any symptoms or signs of infection. Additionally, many people infected with HTLV-I or HTLV-II may never develop any disease caused by the viruses. However, these asymptomatic carriers can still transmit the viruses to others.

MP Diagnostics HTLV Blot 2.4 is manufactured by MP Biomedicals Asia Pacific Pte. Ltd. Singapore, a company of MP Biomedicals LLC, Santa Ana, California.