The Observatory & Fast Facts

Sept. 25, 2018
ZIKA

ZIKV assay approved by FDA for blood screening on the Procleix Panther System. Grifols announced that the FDA approved the Procleix Zika Virus assay for the detection of the virus in individual or pooled plasma specimens from human donors, including volunteer donors of whole blood and blood components for transfusion. The Zika Virus assay is also approved for testing plasma or serum specimens to screen other living (heart-beating) or cadaveric (non-heart beating) organ donors and Human Cells, Tissues, and Cellular, and Tissue-Based Products.

The Procleix Zika Virus assay has been in use since June 2016 under an Investigational New Drug protocol to screen donated blood collected in the U.S. In 2016 the assay was CE-marked for use in European countries conforming to CE Mark regulations. The assay is performed on the Procleix Panther system automated platform using nucleic acid technology (NAT), and enables blood banks and donor centers to enhance the safety of their blood supplies.

The Zika assay project has been funded in whole or in part with Federal funds from the Department of Health and Human Services; Office of the Assistant Secretary for Preparedness and Response; Biomedical Advanced Research and Development Authority, under Contract No. HHSO100201600024C.

Grifols recently received FDA approval for two other assays on the Procleix Panther System—the Procleix Ultrio Elite (for HIV-1, HCV, and HBV and detect HIV-2), and West Nile Virus assays.

The Procleix Panther system automates all aspects of NAT-based blood screening on a single, integrated platform. It eliminates the need for batch processing and combines walk-away freedom with intuitive design for ease of use. The system has received regulatory approvals in countries around the world, including the U.S.

Bloodworks

Newly found enzymes can help turn Type A and B blood into universal Type O. A team of researchers headed by University of British Columbia scientist Stephen Withers reports on enzymes—from the human gut—that remove A or B antigens from red blood cells 30 times more efficiently than previously reported enzymes.

“We have been particularly interested in enzymes that allow us to remove the A or B antigens from red blood cells. If you can remove those antigens, which are just simple sugars, then you can convert A or B to O blood,” Dr. Withers said.

“Scientists have pursued the idea of adjusting donated blood to a common type for a while, but they have yet to find efficient, selective enzymes that are also safe and economical.” To assess potential enzyme candidates more quickly, Withers and colleagues used a technique called metagenomics. “With metagenomics, you take all of the organisms from an environment and extract the sum total DNA of those organisms all mixed up together,”
Withers said.

Casting this wide net allows for the sampling of millions of genes of microorganisms without needing individual cultures. E. coli is then used to select DNA containing genes that code for enzymes that cleave sugar residues.

The team considered sampling DNA from mosquitoes and leeches, the types of organisms that degrade blood, but ultimately found successful candidate enzymes in the human gut microbiome.

Glycosylated proteins called mucins line the gut wall, providing sugars that serve as attachment points for gut bacteria while also feeding them as they assist in digestion.

Some of the mucin sugars are similar in structure to the antigens on A- and B-type blood.

The scientists homed in on the enzymes the bacteria use to pluck the sugars off mucin and found a new family of enzymes that are 30 times more effective at removing red blood cell antigens than previously reported candidates.

Withers and his team are now working to validate the enzymes and test them on a larger scale for potential clinical testing. They also plan to carry out directed evolution, a protein engineering technique that simulates natural evolution. The goal being: creating the most efficient sugar-removing enzyme.

Pregnancy

Blood test may identify gestational diabetes risk in first trimester. A blood test conducted as early as the 10th week of pregnancy may help identify women at risk for gestational diabetes, according to researchers at the National Institutes of Health and other institutions. The study appears in Scientific Reports.

Gestational diabetes occurs only in pregnancy and results when the level of blood sugar, or glucose, rises too high. Gestational diabetes increases the mother’s chances for high blood pressure disorders of pregnancy and the need for cesarean delivery, and the risk for cardiovascular disease and type 2 diabetes later in life. For infants, gestational diabetes increases the risk for large birth size. Unless they have a known risk factor, such as obesity, women typically are screened for gestational diabetes between 24 and 28 weeks of pregnancy.

In the current study, researchers evaluated whether the HbA1c test, commonly used to diagnose type 2 diabetes, could identify signs of gestational diabetes in the first trimester of pregnancy. The test approximates the average blood glucose levels over the previous 2 or 3 months, based on the amount of glucose that has accumulated on the surface of red blood cells.

The researchers analyzed records from the NICHD Fetal Growth Study, a study that recruited more than 2,000 low-risk pregnant women from 12 U.S. clinical sites between 2009 and 2013. The researchers compared HbA1c test results from 107 women who later developed gestational diabetes to test results from 214 women who did not develop the condition. Most of the women had tests at four intervals during pregnancy: early (weeks 8-13), middle (weeks 16-22 and 24-29), and late (weeks 34-37).

Women who went on to develop gestational diabetes had higher HbA1c levels (an average of 5.3 percent), compared to those without gestational diabetes (an average HbA1c level of 5.1 percent). Each .1 percent increase in HbA1c above 5.1 percent in early pregnancy was associated with a 22-percent higher risk for gestational diabetes.

In middle pregnancy, HbA1c levels declined for both groups. However, HbA1c levels increased in the final third of pregnancy, which is consistent with the decrease in sensitivity to insulin that often occurs during this time period.

Transfusions

Mayo Medical Laboratories and National Decision Support Company develop CareSelect Blood. Mayo Clinic implemented a patient blood-management program in 2010 on its Rochester campus and has since experienced a 35 percent reduction of blood transfusions, improving patient outcomes, and achieving significant savings. Using best practices from the program, Mayo Medical Laboratories, the global reference laboratory of Mayo Clinic, collaborated with National Decision Support Company (NDSC) to combine Mayo’s clinical knowledge with NDSC’s expertise in electronic health record (EHR)
clinical-decision support.

Together, Mayo Medical Laboratories and NDSC have developed a new patient blood-management solution called CareSelect Blood. The program will assist healthcare providers with the appropriate utilization of blood products, improving patient care, and reducing costs.

CareSelect Blood features 100 curated transfusion guidelines that are authored and maintained by Mayo Clinic. The platform leverages data from more than 740,000 individual transfusion events. These guidelines can be integrated into a healthcare organization’s EHR within the physician’s workflow to ensure proper ordering.

CareSelect Blood also offers consulting services. They have subject matter experts who visit the healthcare organization to provide training, review of analytics and reports, and discuss the evidence-based transfusion guidelines. The program is customizable for a hospital’s needs—surgery, nursing, or the laboratory.

“The problem is this: too many transfusions, too much waste and an increased probability of adverse outcomes,” says Michael Mardini, CEO of National Decision Support Company. “By expanding our relationship with Mayo Medical Laboratories, we’re able to reduce variation of care, provide reliable standards and report data needed to improve performance. This can lead to improved population health, increased provider efficiency and lower cost of care.”

Heart health

Blood volume in assessing patients with heart failure. Daxor Corporation, a medical instrumentation and biotechnology company focused on blood volume measurement, announced the publication of an investigator-initiated study from Duke University and The Mayo Clinic. The study demonstrates that despite the widespread use of formula-derived estimates of plasma volume in heart failure patients, these methods are inaccurate compared to measured volume using the company’s BVA-100 blood volume measurement diagnostic. The study, “Calculated Estimates of Plasma Volume in Patients with Chronic Heart Failure – Comparison to Measured Volumes” was recently published in the Journal of Cardiac Failure.

“This study shows that indirect assessments of plasma volume or blood volume are limited by their inaccuracy. Our study shows that this is true for formula based volume assessment or the measure of hemoconcentration and similarly poor correlation has previously been shown for the physical exam and even intra-cardiac pressure assessments,” said Marat Fudim, MD, Fellow, Division of Cardiology, Duke University and one of the study authors.

In the study, plasma volume was measured using Daxor’s BVA-100 in 110 patients with clinically stable chronic heart failure. These measurements were correlated using two different plasma volume estimation techniques.

The first was the Kaplan-Hakim formula, which calculates blood volume using a formula calculating hematocrit relative to dry body weight.

The second, the Strauss formula, estimates changes in plasma volume over time using hemoglobin and hematocrit measurement.

The study ultimately showed neither formula demonstrated an accurate blood volume estimate compared to the BVA-100. These formulas varied in their accuracy between just 16 and 68 percent compared to Daxor’s BVA-100, the acknowledged ‘gold-standard’ of volume measurement.