New Studies
Mount Sinai researchers assess accuracy of commercially available lab tests. Scientists from the Icahn School of Medicine at Mount Sinai performed an in-depth comparison of basic blood tests run by commercial laboratories to assess comparability of the tests among the different laboratories, finding that testing service and time of collection significantly influenced results. The study highlights the importance of accuracy and variability of test results.
The study, first designed in early 2015 with data collected last July, analyzed results from comparable blood tests on healthy adults conducted at LabCorp, Quest Diagnostics, and Theranos. Researchers collected multiple samples from the same individuals and controlled for variables such as age, sex, and time of blood collection, among many others, but still found that more than half of test results showed significant differences among test providers. Triglyceride levels and red blood cell counts were among the most consistent results, while white blood cell counts and overall cholesterol levels were among the most variable. Test results from Theranos were flagged by Theranos as abnormal 1.6 times more often than those from LabCorp or Quest. Data from blood samples collected earlier in the day also showed significant differences compared to samples from the same subjects later in the day.
“While most of the variability we found was within clinically accepted ranges, there were several cases where inaccurate results would have led to incorrect medical decisions,” said Joel Dudley, PhD, senior author on the paper.
The study focused on common blood tests, which typically return a single data point or a few data points. However, as Mount Sinai scientists showed, even standard blood tests can generate rich data for statistical analysis: the study collected 14 samples to generate 22 lab results for each of 60 subjects, leading to a total of more than 18,000 data points in this project alone. While most results were within normal ranges, having even a small amount of inaccurate data mixed in could lead to erroneous conclusions from scientific or clinical studies.
Ebola
Research shows potential for emergence of new Ebolavirus. A team from the University of Kent’s (England) School of Biosciences examined the differences between Ebolaviruses that cause severe disease in humans and the Reston virus, which does not.
The Reston virus, which is known to circulate in domestic pigs in Asia and occasionally infect humans, is currently the only member of the Ebolavirus family not to have been reported as causing life-threatening disease, including hemorrhagic fever in humans.
Using computational analysis of the sequences of the genomes of Ebolaviruses and a computational prediction of the effects of sequence variations on virus function, the researchers identified characteristic differences in a number of virus proteins.
The results suggested that only a few changes in one Ebolavirus protein, VP24, may be necessary to turn the Reston virus into a virus that can cause human disease. There may be a risk, therefore, that Reston viruses acquire the few mutations necessary to cause disease in humans and to develop into a novel health threat.
New Zika Assay
First commercial serological tests available for ZIKV detection. EuroImmun AG, a manufacturer of test systems and instruments for medical diagnostics with headquarters in Luebeck, Germany, has developed the first system of comprehensive tests available for the serological detection and differentiation of Zika virus infections. The tests were granted the CE mark in February, making them eligible for sale in the European market. They are available in the U.S. under research use only labeling.
The EuroImmun anti-Zika virus tests, formatted as an enzyme-linked immunosorbent assay (ELISA) and an indirect immunofluorescence assay (IFA), allow for the detection of specific antibodies (IgM and IgG) in the blood of those who may be infected. According to EuroImmun representatives, the tests provide a longer window for detection than the currently available quantitative polymerase chain reaction-based assays alone, making them particularly useful for disease surveillance. The tests can be used to diagnose patients with acute symptoms and to manage asymptomatic cases that fit a risk profile, particularly pregnant women.
The highly specific viral antigen used in the EuroImmun ELISA eliminates cross-reactivity with other flavivirus antibodies, ensuring differentiation from diseases such as dengue fever. The automated antibody detection test kits are suitable for rapid screening of large patient volumes and therefore provide efficient and effective monitoring of the virus spread.
Serological analyses may help determine whether long-term consequences, such as microcephaly and Guillain-Barré syndrome, are a result of a previous Zika virus infection, may be useful for screening sample donations at blood centers and blood banks in hospital settings, and may monitor the growing epidemiological reach of the Zika virus.
Infectious Diseases
New potent nanodrug to combat antibiotic-resistant infections. A research team led by University of Arkansas scientists has developed an alternative therapeutic approach to fighting antibiotic-resistant infections. The novel method uses a targeted, light-activated nanodrug consisting of antibiotic-loaded nanoconstructs, which are nanoscale cages made of gold and coated with polydopamine. The antibiotic is loaded into the polydopamine coating. The gold nanocages convert laser irradiation to heat, resulting in the photothermal effect and simultaneously releasing the antibiotic from the polydopamine coating.
Microbial resistance to antibiotics has become a growing public health concern in hospitals and the community at large, so much so that the Infectious Diseases Society of America has designated six bacterial species as “ESKAPE pathogens”: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species. This designation reflects the limited availability of antibiotics that can be used to treat infections caused by these species.
The team used S. aureus as the proof-of-principle pathogen to demonstrate the potency of its nanodrug. The combination of achieving a photothermal effect and controlled release of antibiotics directly at the site of infection was achieved by laser irradiation at levels within the current safety standard for use in humans. The therapeutic effects of this approach were validated using planktonic bacterial cultures—bacterial cells that are free-floating rather than contained with a biofilm—of both methicillin-sensitive and methicillin-resistant S. aureus strains. However, the method was subsequently shown to be effective even in the context of an intrinsically resistant biofilm.
