Correction: This article has been corrected to clarify that the CDC's test will run on Applied Biosystems' instrument platform, rather than the authorized test being manufactured by Applied Biosystems. GenomeWeb regrets the error.
NEW YORK (GenomeWeb News) – Following on yesterday's report that the US Food and Drug Administration has authorized the emergency use of a molecular diagnostic assay to identify cases of swine flu in the current outbreak, GenomeWeb Daily News has confirmed that the CDC test cited by FDA under the Emergency Use Authorization issued on Sunday will run on an Applied Biosystems instrument platform.
According to a letter sent from FDA to the US Centers for Disease Control and Prevention, the rRT-PCR Swine Flu Panel that has been authorized for use in diagnosing swine influenza A is a real-time assay using TaqMan probes that will be performed by qualified laboratories on Applied Biosystems' 7500 Fast Dx Real-Time PCR instrument or the research use only 7500 Real-Time PCR instrument.
As the swine flu outbreak extends to more cases in the US and additional countries across the globe, a number of molecular diagnostic technology providers are updating existing products or developing new ones that can help identify and distinguish the virus. While several molecular diagnostic makers have released statements to say they may add the flu strain to existing panels or have tests available that can identify swine flu, thus far the CDC test is the only one authorized for testing by FDA.
Joshua Sharfstein, acting commissioner of FDA, said in his letter that that authorization is "limited to the use of the authorized rRT-PCR Swine Flu Panel for the presumptive diagnosis of swine influenza A (H1N1) virus infection for human individuals who are diagnosed with influenza A caused by a virus not subtypeable by currently available FDA-cleared devices."
Mark Stevenson, president and COO of Life Technologies, mentioned yesterday during the firm's first-quarter earnings conference call that the company had "shipped to several government agencies our 7500 Fast and 7500 Fast Dx real time PCR instruments for use in detecting the flu strain and we are in the process of validating one of our influenza kits that can be used to identify this new strain of deadly flu virus."
"What the CDC have worked very carefully to do is make sure that there is standardization in the testing and there is only one authorized test," Stevenson told GenomeWeb today. "You really want to make sure that when you have a suspected case you're identifying the right strain. Some tests may not pick up this new strain."
Stevenson said that the firm already had collaborated with CDC and "supported them last year when we submitted jointly a submission to the FDA to get clearance for the avian influenza assay. The CDC had developed an assay, and we submitted at the same time our 7500 Fast Dx Real-Time PCR instrument to the FDA, which gave clearance."
He also said that the firm had been working with CDC to set up an instrument in the US Public Health Influenza Testing Network. Last week, the CDC contacted Life Technologies and asked the firm "to be able to respond quickly to some of their requests both for instrumentation, people, and fast turnaround on some of the reagents that could be used in their kits."
"We've been working through this public health network to make sure that not only the CDC can do this testing but importantly the public health labs around the world can be equipped to do this standard testing of the suspected cases."
He said distribution of the systems and assays is partly being facilitated by CDC, but the firm also is receiving requests from labs, particularly outside the US. For example, he noted that Mexican authorities are receiving 10 of the Fast Dx Real-Time PCR instruments, which is being helped by the firm's team on the ground in Mexico as well as through help from CDC. Meanwhile, he said local health labs in other parts of the world have contacted Life Technologies directly.
Stevenson could not say how many units the firm has shipped due to the outbreak, but noted that Life Technologies has ramped up production at its Singapore manufacturing facilities to keep up with demand for the instruments as well components for the CDC kits.
"We imagine it's going to be a marathon here, not a sprint. So, we're sort of gearing up for that type of engagement," he said.
While it unknown at this time whether FDA will authorize other molecular diagnostic tests to be used in labs for identifying swine flu cases, several molecular diagnostic makers have let customers know that they have tools available that they believe can help detect cases.
For example, Qiagen said in a statement yesterday that its artus Influenza LC RT PCR Kit and Resplex II 2.0 kit — both of which are presently indicated for research use only — can be used to detect the presence of influenza A sequences, including the H1N1 subtype. The firm has not decided yet whether it will seek to have its products cleared for emergency use, a spokesman told GWDN via e-mail.
CombiMatrix also released a statement saying that it has updated its Influenza-Detection Microarray to include sequence information from the latest strain of the swine flu.
Meanwhile, Luminex, which sells the FDA-cleared xTAG Respiratory Viral Panel, noted that its test can distinguish different subtypes of the flu virus. "A computer-based analysis of the swine flu sequences compared to the primers in the xTAG RVP product indicate that a swine flu positive patient sample is likely to be correctly identified by the portion of the RVP assay which detects the flu A matrix gene," the firm said in a statement. "However, the H1 subtyping portion of the RVP assay is not predicted to identify the swine flu H1 gene, even though the … CDC has identified the swine flu strain as an H1 subtype strain."
Luminex said it is verifying its sequence-based analysis and will provide further updates as soon as possible.
Prodesse, which sells the FDA-cleared ProFlu+ molecular diagnostic assay, said that its test detects the currently circulating swine flu virus. Some of the confirmed cases were detected by the Prodesse assay, the firm's chief marketing officer, Andy Shrago, told GWDN today.
A report in the San Diego Union-Tribune earlier this week also said that the Ibis T5000, which is made by Ibis Bioscience, a firm that Abbott recently bought for $215 million, had identified an early case in the swine flu outbreak at a San Diego medical center. Abbott did not respond to a request seeking further comment.