FDA Approves First Gene-Based Test to Determine Red Blood Cell Types in Transfusion Medicine
Assay helps determine blood compatibility
The FDA has approved the Immucor PreciseType Human Erythrocyte Antigen (HEA) Molecular BeadChip Test (BioArray Solutions Ltd.) — the first FDA-approved molecular assay used in transfusion medicine to assist in determining blood compatibility. The assay can be used to determine donor and patient non-ABO/non-RhD (non-ABO) red blood cell types in the U.S.
The surfaces of red blood cells display minor blood-group antigens in addition to the major ABO blood group antigens. Some people develop antibodies to non-ABO antigens after transfusion or pregnancy. This is especially true in people who may receive repeated blood transfusions, such as those with sickle cell disease. The development of such antibodies can destroy red blood cells if cells with the corresponding antigens are later transfused.
Development of antibodies to non-ABO antigens can be prevented by selecting blood that is better matched to the patient’s non-ABO antigens, the FDA says. In addition, when a potential transfusion recipient has a known antibody that causes red blood cell destruction, red blood cells that are negative for the corresponding antigen must be found.
The identification of red blood cell antigens has traditionally been performed by serological typing. This involves testing blood with reagents (antisera) that are specific for the antigens for which the blood is being tested. However, specific antisera may be scarce or unavailable. The Immucor PreciseType HEA Molecular BeadChip Test provides a new method for determining non-ABO antigens on red blood cells.
“The approval of the Immucor PreciseType HEA Molecular BeadChip Test provides an alternative to serological typing and may enhance patient care in certain situations,” said Karen Midthun, MD, director of the FDA’s Center for Biologics Evaluation and Research.
The Immucor PreciseType HEA Molecular BeadChip Test works by detecting genes that govern the expression of 36 antigens that can appear on the surface of red blood cells. The test uses thousands of coded beads that bind with the genes coding for non-ABO red blood cell antigens that are present in a blood sample. A light signal is generated from each bead that has captured a specific gene. Accompanying computer software decodes the light signals and reports which antigens are predicted to be present on the red cells based on the genes that are detected.
A study was conducted to compare the typing results of the PreciseType HEA Molecular BeadChip Test with that of licensed serological reagents and DNA sequencing. The results demonstrated a comparable performance among the three methods.
The product was brought before the FDA’s Blood Products Advisory Committee on March 18, 2014. After reviewing the relevant information, the committee concluded that the data provided reasonable assurance that the Immucor PreciseType HEA Molecular BeadChip Test is safe and effective for its intended use.
Source: FDA; May 21, 2014.