Keeping you up to date on recent headlines in diagnostics.
Study finds rapid H1N1 tests not advisable when testing for cases ... A study to be published in October in the journal Emerging Infectious Diseases has found that using a rapid diagnostic H1N1 tests (antigen-based testing) for detecting infection is not advisable as its ability to detect positive cases (sensitivity) is low. Of the 144 samples that tested positive for H1N1 virus using RT-PCR (reverse transcription-Polymerase chain reaction), only 16 could be detected when a rapid H1N1 diagnostic test was used, corresponding to a sensitivity of just 11.1%. Rapid diagnostic tests, however, have a high specificity (ability to pick only positive cases). However, specificity is low during non-peak influenza period. The study found that the rapid diagnostic test correctly detected infections only when the viral load was high. Rapid test used by the researchers from the Institute of Virology (Bonn, Germany) was a BinaxNOW Influenza A&B Rapid Test by Inverness Medical (Cologne, Germany). A study undertaken by another team and published in August in the New England Journal of Medicine found that sensitivity was 51% when the QuickVue Influenza assay rapid diagnostic test was used. According to the Centers for Disease and Control (CDC), sensitivity of rapid influenza diagnostic tests for detecting H1N1 ranges from 10-70%. "A negative test result [when rapid test is used] does not rule out influenza A(H1N1) virus infection," it notes. The latest study gains importance as very few studies have been done to compare the sensitivity of RT-PCR and rapid diagnostic tests for H1N1 infection. The limited data that is available also shows that sensitivity of rapid diagnostic tests to detect H1N1 infection is equal to or less than its ability to detect seasonal influenza. According to CDC, lower sensitivity of H1N1 rapid tests could possibly be due to the method of collecting the samples, quality of specimens, time of illness onset to specimen collection, age of the patient, etc. The sensitivity of rapid diagnostic tests is higher in the case of children as they shed more viruses. Unlike a rapid test, the turnaround time when RT-PCR is used is low. Also, shipping the samples, which will be very high during a pandemic, for laboratory-based testing can cause additional problems. Hence a faster way of detecting positive cases using a rapid test becomes attractive. Despite the attractiveness, using a rapid test becomes meaningful and advisable only if it is able to detect most of the positive cases. The researchers conclude that rapid diagnostic H1N1 tests may produce "misleading results in clinical practice. Application of such assays [test kits] should be discouraged in favour of continued molecular diagnostics." Since the sensitivity of a rapid diagnostic H1N1 test is low, the CDC recommends that antiviral therapy should be administered, if appropriate, and infection control measures implemented if clinical suspicion of influenza is high in a patient even though the patient tests negative with a rapid diagnostic test.
ACR forms committee to develop guidelines for CT, MR Imaging data collection ... The American College of Radiology (ACR; Reston, Virginia) has convened a LI-RADS (Liver Imaging Reporting and Data System) Committee to develop a system for standardized reporting and data collection for CT and MR imaging surveillance for hepatocellular carcinoma (HCC). The production of CT-MR LI-RADS will: reduce the frequency of technically inadequate examinations by specifying minimum acceptable technical parameters for CT and MR surveillance imaging procedures; improve communication with clinicians, reduce variability in lesion interpretation, and facilitate meta-analysis of published manuscripts by creating a lexicon of controlled CT and MR terminology; reduce omissions of relevant information from CT and MR reports by standardizing report content and structure, and facilitate outcome monitoring, performance auditing, quality assurance, and research by producing a formal data collection system. "There currently is no formal data collection system, limiting the ability to amass large image databases, share data among institutions, perform data mining, monitor outcomes, give feedback, and assure quality. The committee seeks to address these problems by developing a CT-MR LI-RADS electronic manual to guide the radiology care of patients with or at risk for HCC," said Claude Sirlin, MD, chair of the ACR LI-RADS Committee. LI-RADS is a new method of categorization of liver findings in patients with end stage liver disease. LI-RADS categories will allow radiologists to stratify lesions according to the level of concern for HCC and suggest strategies for follow up and management. "The purpose of the LI-RADS categories is to allow both community and academic radiologists to use terminology that is consistent between centers throughout the country. LI-RADS categories may be used in the development of imaging guidelines and triage for treatment options," Sirlin said.
New study pinpoints where psychotic disorders occur in the brain ... Scanning technology has helped researchers pinpoint the part of the brain that appears to be where psychotic disorders such as schizophrenia begin, a new study says. The research could help doctors diagnose these types of disorders in their early stages and help scientists develop more effective drugs, according to the report in the Sept. 7 issue of the Archives of Psychiatry. In the study, researchers at Columbia University (New York) scanned the brains of 18 people at high risk for psychosis, using a novel high-resolution application of functional MRI technology, an imaging method that tracks which parts of the brain are most active. Seventy percent of the participants who went on to develop disorders such as schizophrenia had very high activity in a region of the hippocampus known as the CA1 subfield, the study authors found. "Right now, the odds of knowing who will go on to develop schizophrenia from [early indications] is only a little better than a coin toss," first author. Scott Schobel PhD, an assistant professor of clinical psychiatry at Columbia University and the New York State Psychiatric Institute, said in a news release. "We're hoping that applying this imaging technique can enhance our knowledge of who might go on to develop schizophrenia and related disorders, since early diagnosis and early intervention are so important."
FAST Diagnostics gets $1M from SBIR technology grant ... FAST Diagnostics (Indianapolis) a developer of a technology for the rapid assessment of kidney function has received additional federal funding to further develop and validate its device technologies. The company, which is based in the Indiana University Emerging Technologies Center (Indianapolis) on the IUPUI campus, is using a $1 million Phase II Small Business Technology Transfer grant from the National Institutes of Health for further development and trials of its early detection technology. Grant procurement assistance was provided by the state's SBIR/STTR office. FAST Diagnostics is also a 2008 recipient of a $2 million grant from the state's 21st Century Research and Technology Fund. FAST Diagnostics' technology tracks the body's kidney function, known as glomerular filtration rate, or GFR, by injecting inert markers into a patient's bloodstream. A fiber optic device inserted into the body through a catheter tracks the molecules, measuring how effectively the body filters waste giving an accurate filtration rate reading in only 40 minutes. Current measurement procedures can take up to 24 hours for an initial reading and several additional hours for follow up readings. "We are very pleased for the National Institutes of Health's additional support for our development of this critical product. It continues to validate not only the soundness of the technology, but the critical need in the market," said Joe Muldoon, CEO of FAST Diagnostics. FAST Diagnostics, which currently employs 12 associates, plans to create up to 65 new research, marketing and sales positions to support the device's commercial launch. FAST Diagnostics' patent-pending diagnostic device and method provides rapid and accurate measurement of true kidney function for use in hospitals, intensive care units, cardiac catheterization labs, and physician offices. This technology gives healthcare providers a valued diagnostic tool for improving outcomes for 3.5 million patients with acute kidney injury annually and the 40 million Americans suffering from chronic kidney disease.
— Compiled by Omar Ford, MDD