Fully Automated Test Screens Blood for Human T-Lymphotropic Virus

A fully automated test is intended for use by laboratories to screen individual donations of blood and plasma for antibodies to human T- lymphotropic virus type I and/or human T- lymphotropic virus type II (anti-HTLV-I/HTLV-II).

HTLV-I and HTLV-II are closely related but distinct retroviruses associated with several diseases including human T-cell leukemia and neurological disorders, according to the U.S. Centers for Disease Control and Prevention (CDC; Atlanta, GA, USA). Screening of the U.S. blood supply for HTLV-I/II began in 1988. The new blood screening test will be performed on the Prism instrument.

The Prism instrument consolidates testing into a single system, automating many of the manual testing procedures and steps currently used to screen blood. Safety features built into the system help track and monitor each sample throughout the testing process providing documentation and quality control for testing facilities. The system can run 160 samples per hour, making it possible to test more than 1,200 samples per eight-hour shift.

The new assay will be used by laboratory technicians to screen individual donations of blood and plasma for antibodies to HTLV-I/HTLV-II. The assay has not been validated for use with pooled specimens and is not intended for use on cord blood specimens, or for the laboratory diagnosis of HTLV-I/HTLV-II infection

Developed by Abbott (Abbott Park, IL, USA), the fully automated Prism test for blood screening has received approval from the U.S. Food and Drug Administration (FDA; Rockville, MD, USA). The Abbott Prism instrument is a completely closed system so that once samples are loaded into the instrument, the inner-workings of the analyzer take-over and process samples similar to the manner in which an assembly line operates. Samples are transported through each station of the instrument where data is recorded automatically as the instrument analyzes the sample for evidence of exposure to viruses. When the screening process is complete, the samples are removed.

Numerous safety features built into the system help track and monitor each sample providing documentation and quality control for testing facilities. Additionally, Abbott Prism's testing methodology, chemiluminescent immunoassay (ChLIA), allows the system to detect infectious agents or antibodies, which are present in a sample.

Chemiluminescence is the emission of light or photons as a result of a chemical reaction. In chemiluminescence, an excited electron state is created by a chemical treatment of the luminescing compound. When the electrons move from this "excited” or more energetic state back to their more natural "relaxed” state, they release energy in the form of light.

In the Abbott Prism system, a chemiluminescent marker is activated, causing luminescence to immediately occur. This "flash” of light produced by the reaction is measured and quantified, becoming the basis of the test result.

The Prism system also includes four hepatitis tests: a core hepatitis B test (Prism HBcore); two hepatitis B surface antigen tests (Prism HBsAg and HBsAg confirmatory); and a hepatitis C test (Prism HCV), introduced in July 2007. These tests are used in more than 30 countries.


Related Links:
U.S. Centers for Disease Control and Prevention
Abbott
U.S. Food and Drug Administration