Tuesday, November 30, 2010

Hepatitis B PCR-based molecular diagnostic solution

Novel molecular diagnostics solutions meet demand for fast, accurate testing

The first real-time tests for tuberculosis and drug resistant tuberculosis and a way to measure the viral load or amount of hepatitis B virus in a blood sample are among the advances in molecular diagnostic technology. Sean Ottewell reports.
The emergence and spread of drug-resistant mycobacterium tuberculosis (TB) threatens global TB control efforts, and there is an urgent need for new diagnostic tests that rapidly identify drug sensitivity profiles of TB strains.

To help address these concerns, Seegene has introduced Anyplex MDR-TB screening test, which it says is the first real-time PCR molecular diagnostic capable of simultaneous detection of TB and genetic mutations leading to multi-drug resistant TB (MDR-TB) within four hours.
According to the World Health Organisation (WHO), TB strains that are resistant to all major anti-TB drugs have been documented in every country by the non-governmental organisation recent survey. A particularly dangerous form of drug-resistant TB is multi-drug resistant TB (MDR-TB), which is defined as the disease caused by TB bacilli resistant to, among others, the two most powerful anti-TB drugs, isoniazid (INH) and rifampicin (Rif).The rate for successful MDR-TB treatment is extremely low and the progress of the disease is faster than normal TB, resulting in 40-50 per cent of mortality rate. Rates of MDR-TB are troublingly high in some countries, especially in the former Soviet Union, and threaten TB infectious disease control efforts. WHO estimates that more than 440 000 people are infected with MDR-TB.
Using Anyplex MDR-TB screening test, healthcare workers will be able to quickly determine whether or not a patient is infected with a strain of TB that is resistant to INH and Rif. The Anyplex MDR-TB is a real-time detection test of M. tuberculosis that quickly and comprehensively determines the levels of targets in a patient's various sample types, and identifies mutations of drug resistant genes to better inform a diagnosis.
Because genetic mutations that lead to antibiotic resistance are minute and sit close together, so far conventional PCR or conventional real-time PCR tests are not able to discriminate these mutations accurately within the same test procedure. In contrast, the Anyplex MDR-TB test can detect the mutations of drug resistant genes to Rif (rpoB: D516V/Y, H526D/Y, S531L) and INH (katG: S315T (2 cases); inhA promoter: -15(C/T)).
According to Seegene, the unprecedented speed and accuracy of the Anyplex MDR-TB tests will enable doctors and clinicians to quickly provide an appropriate treatment to prevent the spread of MDR-TB.

Seegene's new MDR-TB test takes TB diagnostics to a new level. Current TB test methods are hindered by speed (culture typically required 2-8 weeks for results), low sensitivity (acid-fast bacilli smear microscopy produced results in 24 hours but at the cost of missing a significant portion of TB cases) and low specificity (culture and microscopy methods not being able to efficiently differentiate between M. tuberculosis and non-tuberculosis mycobacteria). Furthermore, none of these approaches are able to rapidly and efficiently identify a patient's resistance to the major drugs for treating TB - INH and Rif. Even if sequencing and line probe assay are available to test drug resistance, the procedures are quite complicated and time-consuming.

"Making a fast and accurate diagnosis of the type of TB infection a patient may have is the most important step to curing a patient. Because MDR-TB is difficult to treat, preventing its spread throughout the population is essential. The Anyplex MDR-TB test is a powerful new tool that healthcare workers can use to rapidly determine MDR-TB infections, which will both help stop it from spreading and allow health care professionals to set a course of alternative medications for infected patients," said Jong-Yoon Chun, chief executive officer of Seegene.
Molecular testing

QIAGEN has also launched a novel, automated PCR-based molecular diagnostic solution. Called QIAsymphony RGQ, the company says it sets new standards for molecular testing and incorporates all workflow steps from sample to detection. It offers many features which create exceptional flexibility, such as continuous loading, random access, open channels for user-developed tests, the broadest menu of commercial assays as well as the ability to process an almost unlimited range of sample types. This, says the company, provides laboratories with a system that transforms their work in the emerging field of molecular diagnostics (Fig. 1).
Data integration

This new solution is comprised of modules that can be used as standalone systems or combined into a fully integrated system. The QIAsymphony RGQ system comprises the physical and data integration of the modules QIAsymphony SP for sample preparation, QIAsymphony AS for assay setup, and the Rotor-Gene Q real time PCR thermocycler. QIAsymphony also provides the broadest available PCR-based assay menu, including the artus real time PCR kits for the detection of HIV, HCV, HBV, and a transplantation panel with CMV, EBV, HSV, VZV and BKV.
A large pipeline of further tests will be launched in the coming months, including therascreen EGFR, KRAS, as well as artus Influenza, CT, CT/Ng and an extended transplantation panel. Many more tests are in development as well as the ability to integrate detection options such as pyrosequencing, and multiplexing solutions.
"Our new integrated and validated QIAsymphony RGQ system has been developed to meet the testing needs of molecular diagnostic laboratories now and in the future", said Peer Schatz, QIAGEN's ceo.

Micronics has announced that the US Department of Defence has awarded the company a US$2.6m applied research and technology development award under the US Army medical research and material command's polytrauma and blast injury project for advancement of its PanNAT system for point-of-care molecular diagnosis of infectious pathogens.
The armed forces are interested in innovative medical technology to develop a highly accurate, rapid assay device for detecting bloodborne pathogens. The device needed would have a higher degree of sensitivity than existing equipment, and provide instant results, while being durable and fully functional in field testing to withstand wartime conditions.
In response, the Micronics says that PanNAT technology represents a significant advance over current nucleic acid-based assay systems, which are complex, expensive and can take several hours or days. PanNAT system is a sample-to-answer device that is easy to use; the lightweight, portable instrument processes a cartridge into which all reagents are incorporated for rapid disease detection.

The award will advance the development of assays on the compact, WiFi-enabled, mains and/or battery-powered PanNAT instrument for the direct detection of multiple bloodborne pathogens in fresh blood samples. The specific pathogens to be detected are those for hepatitis B and C (HBV, HCV) as well as the human immunodeficiency virus (HIV). The assay is intended for use in the battlefield to screen out any infectious blood donated for transfusion.
Measuring viral load

Meanwhile Abbott has received approval from the US Food and Drug Administration (FDA) to market the RealTime HBV assay for measuring viral load or the amount of hepatitis B virus (HBV) in a patient's blood. It is the first and only approved test capable of automating HBV viral load testing from sample extraction to final results. The assay is intended for use as an aid in the management of patients with chronic HBV infection undergoing anti-viral therapy. It can be used to measure HBV DNA levels at baseline and during treatment to aid in assessing response to treatment. Assay results must be interpreted within the context of all relevant clinical and lab findings. Use of the assay to determine the clinical stage of HBV infection has not been established. Clinical performance characteristics have been established for individuals treated with adefovir dipivoxil. The assay is not intended as a screening test for HBV or as a diagnostic test for confirming the presence of HBV infection.

"The Abbott RealTime HBV assay, which is the first and only automated HBV viral load test approved by the FDA, is an important tool for helping physicians make and adjust treatment decisions for newly-diagnosed patients and those taking anti-viral medications," said Stafford O'Kelly, head of Abbott's molecular diagnostics business. "The test will also help improve laboratory productivity by automating the most labour intensive steps of HBV testing."
Abbott's molecular HBV assay detects and measures all known HBV genotypes (A-H) by targeting an essential, highly conserved segment of the HBV genome. The capability for detecting HBV genotypes is important for both monitoring the disease and guiding treatment decisions.

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