American Association for Clinical Chemistry
Better health through laboratory medicine
July 2007 Clinical Laboratory News: News From the FDA

July 2007: Volume 33, Number 7

AspirinWorks Test Kit Cleared

Corgenix Medical Corporation (Denver, Colo.) announced the FDA clearance of its AspirinWorks test kit, an ELISA that determines levels of 11-dehydro thromboxane B2 (11dhTx B2) in human urine. The test aids in the qualitative detection of aspirin resistance in apparently healthy patients after ingestion. Unlike other platelet aggregation tests that require evaluation of freshly-drawn blood within 4 hours, the AspirinWorks test only requires a urine sample that can be obtained in a doctor’s office.

FDA Approves Implantable Continuous Glucose Monitor

Based on its effectiveness in detecting trends and tracking patterns in glucose levels, the FDA announced approval of the STS-7 continuous glucose monitoring system. Marketed by DexCom (San Deigo, Calif.), the STS-7 measures glucose levels every 5 minutes for 7 days, revealing patterns that traditional fingerstick methods don’t pick up. In particular, the STS-7 can detect when glucose levels drop overnight and show how levels fluctuate between meals or in response to exercise. The system uses a self-implanted sensor that lies just below the skin in the abdomen which measures glucose in interstitial fluid and must be replaced each week. A wireless receiver contains the display and can also sound an alarm if the patient’s glucose dips or rises outside of pre-programmed levels. FDA approved a 3-day version of the device in March of last year.

Two HIV-1 Viral Load Assays Cleared

The FDA cleared two HIV-1 PCR assays, one from Abbott (Abbott Park, Ill.) for its m2000 instrument and another from Roche (Pleasanton, Calif.) on its Cobas Ampliprep and Cobas TaqMan instruments.

Abbott’s Real Time HIV-1 viral load test is designed to detect and precisely measure viral load, including three major groups of HIV-1 as well as non-B subtypes. It is intended for use as a marker of disease progression and as an aid in assessing viral response to antiretroviral treatment.

Roche’s Cobas Ampliprep/Cobas TaqMan HIV-1 test is the first fully-automated HIV-1 test using real-time PCR in the U.S., according to Roche. Intended for monitoring disease progress and response to therapy, Roche said the assay can provide a broader range of viral load data than earlier generation tests. The test requires that the Ampliprep and TaqMan instruments be docked in a sample-in/results-out configuration in order to eliminate manual intervention between steps.

Enzymatic Creatinine Reagent Cleared

Thermo Fisher Scientific (Pittsburgh, Pa.) announced FDA clearance for its new liquid stable enzymatic creatinine reagent. The reagent has a higher specificity for creatinine to overcome interference problems associated with the kinetic Jaffe reagent. The reagent uses a peroxidase-PAP (4-aminoantypyrine) indicator system, making it compatible with automated analyzers.

FDA Tackles Emerging Influenza A Virus Tests

A new FDA guidance focuses on making sure that IVDs meant to generally detect influenza A (or A/B) viruses directly from patient samples carry labels that clearly indicate which novel A subtypes may go undetected. The guidance indicates that in most instances a new 510(k) submission will not be necessary to make a label change; however, the guidance recommends a 6-month month deadline for manufacturers to tweak their labels if needed. The guidance, “In Vitro Diagnostic Devices to Detect Influenza A Viruses: Labeling and Regulatory Path,” is available online.

MRSA Test Categorized at Moderate Complexity

Cepheid (Sunnyvale, Calif.) announced that the FDA has categorized its Xpert MRSA test for the rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) as moderate complexity under CLIA. First cleared for marketing in April, the assay is the first molecular diagnostic MRSA test to receive the moderate complexity status from the FDA. The assay runs on the company’s GeneXpert system and can deliver results in less than 2 hours.