Of Special Interest to Laboratorians/LabNet
MedSun: Newsletter #18, November 2007
CLIA Waiver Granted by FDA for i-STAT® CHEM8+ Test Cartridge
The Office of In Vitro Diagnostics (OIVD) of the Food and Drug Administration (FDA) has granted Clinical Laboratory Improvement Amendments of 1988 (CLIA)-waived status to the Abbott Point of Care i-STAT CHEM8+ test cartridge. The CHEM8+ test cartridge is a single-use, in vitro diagnostic test cartridge that measures sodium, potassium, chloride, total carbon dioxide, glucose, urea, creatinine, ionized calcium, and hematocrit in arterial, venous, and capillary whole blood samples. The CLIA waiver makes the handheld test cartridge more widely available for use to health care providers when a faster turnaround in results may be needed, such as in physicians’ offices, emergency departments, intensive care units, operating rooms, and outpatient clinics. The CHEM8+ test cartridge is the first i-STAT cartridge to receive a CLIA waiver.
FDA Clears Genetic Lab Test for Warfarin Sensitivity
On September 17, 2007, the U.S. Food and Drug Administration cleared for marketing a new genetic test that will help physicians assess whether a patient may be especially sensitive to the blood-thinning drug warfarin (Coumadin), which is used to prevent potentially fatal clots in blood vessels.
One-third of patients receiving warfarin metabolize it quite differently than expected and experience a higher risk of bleeding. Research has shown that some of the unexpected response to warfarin depends on variants of two genes, CYP2C9 and VKORC1. The Nanosphere Verigene Warfarin Metabolism Nucleic Acid Test detects some variants of both genes.
"Today’s action offers physicians the first FDA-cleared genetic test for warfarin sensitivity, which is another step in our commitment to personalized medicine,” said Daniel Schultz, M.D., director, FDA’s Center for Devices and Radiological Health. “With this test, physicians may be able to use genetic information along with other clinical information to treat their patients.”
Warfarin can be a difficult drug to use because the optimal dose varies depending on many risk factors, including a patient's diet, age, and the use of other medications. Rapidly achieving the correct dose is important. Patients who receive doses that are higher than needed to correctly thin the blood are at risk of life-threatening bleeding. Those who receive doses that are too low may remain at risk of life-threatening blood clots.
Warfarin is the second most common drug, after insulin, implicated in emergency room visits for adverse drug events.
In August, FDA approved updated labeling for Coumadin, the brand name version of warfarin, explaining that people with variations of the genes CYP2C9 and VKORC1 may respond differently to the drug. Manufacturers of generic warfarin are adding similar information to their products' labeling.
Physicians and other health care professionals who prescribe warfarin regularly check to see if the drug is working properly by ordering a test called the PT or prothrombin time that evaluates the blood's ability to clot properly. The results are measured in seconds and compared with the expected value in healthy people, known as the International Normalized Ratio or INR.
The Nanosphere test is not intended to be a stand-alone tool to determine optimum drug dosage, but should be used along with clinical evaluation and other tools, including INR, to determine the best treatment for patients.
FDA cleared the test based on results of a study conducted by the manufacturer of hundreds of DNA samples as well as on a broad range of published literature. In a three site study, the test was accurate in all cases where the test yielded a result; 8 percent of the tests could not identify which genetic variants were present.
The new test was cleared for use on the Verigene System, a clinical laboratory test system. Both products are manufactured by Nanosphere Inc., Northbrook, Ill.
FDA Licenses 15 New Blood Typing Tests
Tests help ensure safe blood transfusions for patients
On September 14, 2007, the U.S. Food and Drug Administration licensed 15 new blood typing tests that were previously unavailable in the United States.
These tests, known as blood grouping reagents, are used to determine the blood type of blood donors, an essential step in ensuring safe blood transfusion for patients. If mismatched blood is administered to a patient, it may cause a serious and potentially fatal reaction. To prevent such problems, people must receive compatible blood based on the results of blood typing tests.
The newly approved ALBAclone Blood Grouping Reagents include the common ABO and Rh tests, plus tests for rare blood types. The reagents are monoclonal antibodies, highly specific antibodies that ensure product uniformity and availability.
"The licensing of these reagents will provide more choice for blood establishments and transfusion services and may facilitate testing for rare blood groups," said Jesse L. Goodman, M.D., M.P.H., director of FDA's Center for Biologics Evaluation and Research. "Licensure of these additional blood grouping reagents will help ensure a more stable supply of these tests, especially important in the event of a product shortage."
The reagents are manufactured by Alba Bioscience, Inc. of Durham, North Carolina.
FDA Approves Second West Nile Virus Screening Test for Donated Blood and Organs
The U.S. Food and Drug Administration announced on August 28, 2007, approval of a second test for the detection of West Nile virus (WNV) in blood and organs.
The cobas TaqScreen WNV test is an automated test that's able to detect the genetic material of the virus itself early in the infection. Such nucleic acid testing improves blood and organ safety, detecting whether donated blood and organs have been infected even before the donor's body has begun to produce antibodies against the virus.
Most often, WNV is transmitted to humans by mosquitoes. But WNV can also be transmitted by blood transfusion or organ transplantation from infected donors. While WNV infection is common in Africa, Asia, and the Middle East, it did not appear in the United States until 1999. Since then, WNV has become endemic in most of this country, with from 1 million to 3 million cases between 1999 and 2006, according to the Centers for Disease Control and Prevention (CDC).
"This action is the culmination of the dedicated efforts of FDA, our sister agencies, blood establishments, and manufacturers to bring donor screening tests to market for this increasingly common virus," said Jesse L. Goodman, M.D., M.P.H., director of FDA's Center for Biologics Evaluation and Research. "As a result, blood centers and hospitals now have a choice of two FDA approved tests to screen for West Nile Virus in donated blood and organs."
Most people infected with WNV show no signs of the disease but about 1 in 150 to 1 in 350 infected people will develop serious symptoms, including encephalitis, an inflammation of the brain. Since the introduction of the virus, the reported number of human cases of serious WNV in the United States has grown steadily from 62 in 1999 to 4,269 in 2006.
WNV has been especially virulent this year. Although it is still early in the WNV season, 58 blood donors who are possibly positive for the virus have been reported to the CDC as of August 21, 2007.
The cobas TaqScreen WNV test is approved for the detection of the virus in plasma specimens from human donors of whole blood and blood components (plasma, red or white cells, platelets) and living donors of cells, reproductive cells and other tissues. It is also intended for use in testing plasma specimens of organ donors when specimens are obtained while the donor's heart is still beating. The test is not intended for use on samples of cord blood or as an aid in the diagnosis of WNV infection.
Approval comes as FDA is preparing guidance on the use of licensed WNV screening tests for blood donors.
The test is manufactured by Roche Molecular Systems Inc. of Pleasanton, California.
For further details, refer to the Abbott Point of Care October 2, 2007, press release at