Though PCR clinical laboratory testing is widely used, some scientists are concerned its specificity may limit the ability to identify all variants of bird flu in wastewater
Wastewater testing of infectious agents appears to be here to stay. At the same time, there are differences of opinion about which methodologies and clinical laboratory tests are best suited to screen for specific contagions in wastewater. One such contagion is avian influenza, the virus that causes bird flu.
Wastewater testing by public health officials became a valuable tool during the COVID-19 pandemic and has now become a common method for detecting other diseases as well. For example, earlier this year, scientists used wastewater testing to learn how the H5N1 variant of the bird flu virus was advancing among dairy herds across the country.
In late March, the bird flu was first detected in dairy cattle in Texas, prompting scientists to begin examining wastewater samples to track the virus. Some researchers, however, expressed concerns about the ability of sewage test assays to detect all variants of certain diseases.
“Right now we are using these sort of broad tests to test for influenza A viruses,” Denis Nash, PhD, Distinguished Professor of Epidemiology at City University of New York (CUNY) and Executive Director of CUNY’s Institute for Implementation Science in Population Health (SPH), told the Los Angeles Times. “It’s possible there are some locations around the country where the primers being used in these tests might not work for H5N1.” Clinical laboratory PCR genetic testing is most commonly used to screen for viruses in wastewater. (Photo copyright: CUNY SPH.)
Effectiveness of PCR Wastewater Testing
Polymerase chain reaction (PCR) tests are most commonly used to distinguish genetic material related to a specific illness such as the flu virus. For PCR tests to correctly identify a virus, the tests must be designed to look for a specific subtype. The two most prevalent human influenza A viruses are known as H1N1 (swine flu) and H3N2, which was responsible for the 1968 pandemic that killed a million people worldwide. The “H” stands for hemagglutinin and the “N” for neuraminidase.
Hemagglutinin is a glycoprotein that assists the virus to attach to and infect host cells. Neuraminidase is an enzyme found in many pathogenic or symbiotic microorganisms that separates the links between neuraminic acids in various molecules.
Avian flu is also an influenza A virus, but it has the subtype H5N1. Although human and bird flu viruses both contain the N1 signal, they do not share an H. Some scientists fear that—in cases where a PCR test only looks for H1 and H3 in wastewater—that test could miss the bird flu altogether.
“We don’t have any evidence of that. It does seem like we’re at a broad enough level that we don’t have any evidence that we would not pick up H5,” Jonathan Yoder, Deputy Director, Infectious Disease Readiness and Innovation at the US Centers for Disease Control and Prevention (CDC) told the Los Angeles Times.
The CDC asserts current genetic testing methods are standardized and will detect the bird flu. Yoder also affirmed the tests being used at all the testing sites are the same assay, based on information the CDC has published regarding testing for influenza A viruses.
Genetic Sequencing Finds H5N1 in Texas Wastewater
In an article published on the preprint server medRxiv titled, “Virome Sequencing Identifies H5N1 Avian Influenza in Wastewater from Nine Cities,” the authors wrote, “using an agnostic, hybrid-capture sequencing approach, we report the detection of H5N1 in wastewater in nine Texas cities, with a total catchment area population in the millions, over a two-month period from March 4th to April 25th, 2024.”
The authors added, “Although human to human transmission is rare, infection has been fatal in nearly half of patients who have contracted the virus in past outbreaks. The increasing presence of the virus in domesticated animals raises substantial concerns that viral adaptation to immunologically naïve humans may result in the next flu pandemic.”
“So, it’s not just targeting one virus—or one of several viruses—as one does with PCR testing,” Eric Boerwinkle, PhD, Dean of the UTHealth Houston School of Public Health told the LA Times. “We’re actually in a very complex mixture, which is wastewater, pulling down viruses and sequencing them. What’s critical here is it’s very specific to H5N1.”
Epidemiologist Blake Hanson, PhD, Assistant Professor, Department of Epidemiology, Human Genetics, and Environmental Sciences at the UT Health Houston Graduate School of Biomedical Science, agreed with Boerwinkle that though the PCR-based methodology is highly effective at detecting avian flu in wastewater samples, the testing can do more.
“We have the ability to look at the representation of the entire genome, not just a marker component of it. And so that has allowed us to look at H5N1, differentiate it from some of our seasonal fluids like H1N1 and H3N2,” Hanson told the LA Times. “It’s what gave us high confidence that it is entirely H5N1, whereas the other papers are using a part of the H5 gene as a marker for H5.”
Human or Animal Sources
Both Boerwinkle and Hanson are epidemiologists in the team studying wastewater samples for H5N1 in Texas. They are not sure where the virus originated but are fairly certain it did not come from humans.
“Texas is really a confluence of a couple of different flyways for migratory birds, and Texas is also an agricultural state, despite having quite large cities,” Boerwinkle noted. “It’s probably correct that if you had to put your dime and gamble what was happening, it’s probably coming from not just one source but from multiple sources. We have no reason to think that one source is more likely any one of those things.”
“Because we are looking at the entirety of the genome, when we look at the single human H5N1 case, the genomic sequence has a hallmark amino acid change, compared to all of the cattle from that same time point,” Hanson said. “We do not see that hallmark amino acid present in any of our sequencing data. And we’ve looked very carefully for that, which gives us some confidence that we’re not seeing human-human transmission.”
CDC Updates on Bird Flu
In its weekly updates on the bird flu situation, the CDC reported that 48 states have outbreaks in poultry and 14 states have avian flu outbreaks in dairy cows. More than 238 dairy herds have been affected and, as of September 20, over 100 million poultry have been affected by the disease.
In addition, the CDC monitored more than 4,900 people who came into contact with an infected animal. Though about 230 of those individuals have been tested for the disease, there have only been a total of 14 reported human cases in the US.
The CDC posts information specifically for laboratory workers, healthcare providers, and veterinarians on its website.
The CDC also states that the threat from avian flu to the general public is low. Individuals at an increased risk for infection include people who work around infected animals and those who consume products containing raw, unpasteurized cow’s milk.
Symptoms of H5N1 in humans may include fever or chills, cough, headaches, muscle or body aches, runny or stuffy nose, tiredness and shortness of breath. Symptoms typically surface two to eight days after exposure.
Scientists and researchers have been seeking a reliable clinical laboratory test for disease organisms in a fast, accurate, and cost-effective manner. Wastewater testing of infectious agents could fulfill those goals and appears to be a technology that will continue to be used for tracking disease.
Palmetto GBA’s Chief Medical Officer will cover how clinical laboratories billing for genetic testing should prepare for Z-Codes at the upcoming Executive War College in New Orleans
After multiple delays, UnitedHealthcare (UHC) commercial plans will soon require clinical laboratories to use Z-Codes when submitting claims for certain molecular diagnostic tests. Several private insurers, including UHC, already require use of Z-Codes in their Medicare Advantage plans, but beginning June 1, UHC will be the first to mandate use of the codes in its commercial plans as well. Molecular, anatomic, and clinical pathologist Gabriel Bien-Willner, MD, PhD, who oversees the coding system and is Chief Medical Officer at Palmetto GBA, expects that other private payers will follow.
“A Z-Code is a random string of characters that’s used, like a barcode, to identify a specific service by a specific lab,” Bien-Willner explained in an interview with Dark Daily. By themselves, he said, the codes don’t have much value. Their utility comes from the DEX Diagnostics Exchange registry, “where the code defines a specific genetic test and everything associated with it: The lab that is performing the test. The test’s intended use. The analytes that are being measured.”
The registry also contains qualitative information, such as, “Is this a good test? Is it reasonable and necessary?” he said.
Molecular, anatomic, and clinical pathologist Gabriel Bien-Willner, MD, PhD (above), Palmetto GBA’s Chief Medical Officer, will speak about Z-Codes and the MolDX program during several sessions at the upcoming Executive War College on Diagnostics, Clinical Laboratory, and Pathology Management taking place in New Orleans on April 30-May 1. Clinical laboratories involved in genetic testing will want to attend these critical sessions. (Photo copyright: Bien-Willner Physicians Association.)
Palmetto GBA Takes Control
Palmetto’s involvement with Z-Codes goes back to 2011, when the company established the MolDX program on behalf of the federal Centers for Medicare and Medicaid Services (CMS). The purpose was to handle processing of Medicare claims involving genetic tests. The coding system was originally developed by McKesson, and Palmetto adopted it as a more granular way to track use of the tests.
In 2017, McKesson merged its information technology business with Change Healthcare Holdings LLC to form Change Healthcare. Palmetto GBA acquired the Z-Codes and DEX registry from Change in 2020. Palmetto GBA had already been using the codes in MolDX and “we felt we needed better control of our own operations,” Bien-Willner explained.
In addition to administering MolDX, Palmetto is one of four regional Medicare contractors who require Z-Codes in claims for genetic tests. Collectively, the contractors handle Medicare claims submissions in 28 states.
Benefits of Z-Codes
Why require use of Z-Codes? Bien-Willner explained that the system addresses several fundamental issues with molecular diagnostic testing.
“Payers interact with labs through claims,” he said. “A claim will often have a CPT code [Current Procedural Technology code] that doesn’t really explain what was done or why.”
In addition, “molecular diagnostic testing is mostly done with laboratory developed tests (LDTs), not FDA-approved tests,” he said. “We don’t see LDTs as a problem, but there’s no standardization of the services. Two services could be described similarly, or with the same CPT codes. But they could have different intended uses with different levels of sophistication and different methodologies, quality, and content. So, how does the payer know what they’re paying for and whether it’s any good?”
When the CPT code is accompanied by a Z-Code, he said, “now we know exactly what test was done, who did it, who’s authorized to do it, what analytes are measured, and whether it meets coverage criteria under policy.”
The process to obtain a code begins when the lab registers for the DEX system, he explained. “Then they submit information about the test. They describe the intended use, the analytes that are being measured, and the methodologies. When they’ve submitted all the necessary information, we give the test a Z-Code.”
The assessment could be as simple as a spreadsheet that asks the lab which cancer types were tested in validation, he said. On the other end of the scale, “we might want to see the entire validation summary documentation,” he said.
Commercial Potential
Bien-Willner joined the Palmetto GBA in 2018 primarily to direct the MolDX program. But he soon saw the potential use of Z-Codes and the DEX registry for commercial plans. “It became instantly obvious that this is a problem for all payers, not just Medicare,” he said.
Over time, he said, “we’ve refined these processes to make them more reproducible, scalable, and efficient. Now commercial plans can license the DEX system, which Z-Codes are a part of, to better automate claims processing or pre-authorizations.”
In 2021, the company began offering the coding system for Medicare Advantage plans, with UHC the first to come aboard. “It was much easier to roll this out for Medicare Advantage, because those programs have to follow the same policies that Medicare does,” he explained.
As for UHC’s commercial plans, the insurer originally planned to require Z-Codes in claims beginning Aug. 1, 2023, then pushed that back to Oct. 1, according to Dark Daily’s sister publication The Dark Report.
Then it was pushed back again to April 1 of this year, and now to June 1.
“The implementation will be in a stepwise fashion,” Bien-Willner advised. “It’s difficult to take an entirely different approach to claims processing. There are something like 10 switches that have to be turned on for everything to work, and it’s going to be one switch at a time.”
For Palmetto GBA, the commercial plans represent “a whole different line of business that I think will have a huge impact in this industry,” he said. “They have the same issues that Medicare has. But for Medicare, we had to create automated solutions up front because it’s more of a pay and chase model,” where the claim is paid and CMS later goes after errors or fraudulent claims.
“Commercial plans in general just thought they could manually solve this issue on a claim-by-claim basis,” he said. “That worked well when there was just a handful of genetic tests. Now there are tens of thousands of tests and it’s impossible to keep up.
They instituted programs to try to control these things, but I don’t believe they work very well.”
Bien-Willner is scheduled to speak about Palmetto GBA’s MolDX program, Z-Codes, and related topics during three sessions at the upcoming 29th annual Executive War College conference. Clinical laboratory and pathology group managers would be wise to attend his presentations. Visit here (or paste this URL into your browser: https://www.executivewarcollege.com/registration) to learn more and to secure your seat in New Orleans.
New nanotechnology device is significantly faster than typical rapid detection clinical laboratory tests and can be manufactured to identify not just COVID-19 at point of care, but other viruses as well
Researchers at the University of Central Florida (UCF) announced the development of an optical sensor that uses nanotechnology to identify viruses in blood samples in seconds with an impressive 95% accuracy. This breakthrough underscores the value of continued research into technologies that create novel diagnostic tests which offer increased accuracy, faster speed to answer, and lower cost than currently available clinical laboratory testing methods.
The innovative UCF device uses nanoscale patterns of gold that reflect the signature of a virus from a blood sample. UCF researchers claim the device can determine if an individual has a specific virus with a 95% accuracy rate. Different viruses can be identified by using their DNA sequences to selectively target each virus.
According to a UCF Today article, the University of Central Florida research team’s device closely matches the accuracy of widely-used polymerase chain reaction (PCR) tests. Additionally, the UCF device provides nearly instantaneous results and has an accuracy rate that’s a marked improvement over typical rapid antigen detection tests (RADT).
“The sensitive optical sensor, along with the rapid fabrication approach used in this work, promises the translation of this promising technology to any virus detection, including COVID-19 and its mutations, with high degree of specificity and accuracy,” Debashis Chanda, PhD, told UCF Today. Chanda is professor of physics at the NanoScience Technology Center at UCF and one of the authors of the study. “Here, we demonstrated a credible technique which combines PCR-like genetic coding and optics on a chip for accurate virus detection directly from blood.”
The team tested their device using samples of the Dengue virus that causes Dengue fever, a tropical disease spread by mosquitoes. The device can detect viruses directly from blood samples without the need for sample preparation or purification. This feature enables the testing to be timely and precise, which is critical for early detection and treatment of viruses. The chip’s capability also can help reduce the spread of viruses.
No Pre-processing or Sample Preparation Needed for Multi-virus Testing
The scientists confirmed their device’s effectiveness with multiple tests using varying virus concentration levels and solution environments, including environments with the presence of non-target virus biomarkers.
“A vast majority of biosensors demonstrations in the literature utilize buffer solutions as the test matrix to contain the target analyte,” Chanda told UCF Today. “However, these approaches are not practical in real-life applications because complex biological fluids, such as blood, containing the target biomarkers are the main source for sensing and at the same time the main source of protein fouling leading to sensor failure.”
The researchers believe their device can be easily adapted to detect other viruses and are optimistic about the future of the technology.
“Although there have been previous optical biosensing demonstrations in human serum, they still require off-line complex and dedicated sample preparation performed by skilled personnel—a commodity not available in typical point-of-care applications,” said Abraham Vazquez-Guardado, PhD, a Postdoctoral Fellow at Northwestern University who worked on the study, in the UCS Today article. “This work demonstrated for the first time an integrated device which separated plasma from the blood and detects the target virus without any pre-processing with potential for near future practical usages.”
More research and additional studies are needed to develop the University of Central Florida scientists’ technology and prove its efficacy. However, should the new chip prove viable for point-of-care testing, it would give clinical laboratories and microbiologists an ability to test blood samples without any advanced preparation. Combined with the claims for the device’s remarkable accuracy, that could be a boon not only for COVID-19 testing, but for testing other types of viruses as well.
In an out-of-court settlement, two commercial clinical laboratory companies also agreed to reduce their prices for rapid antigen tests as well
How clinical laboratory companies were pricing their COVID-19 tests caught the attention of government authorities in South Africa. Government agencies in that country are establishing what they view as fair clinical laboratory pricing for private COVID-19 PCR (polymerase chain reaction) and rapid antigen tests without turning to litigation or fines.
The Competition Commission (Commission) is an organization charged with reviewing and acting on business practices in South Africa. In a December 11, 2021, news release, the Commission said it had reached a “ground-breaking agreement” with two private laboratories—Ampath and Lancet—to reduce their COVID-19 PCR test prices from 850 South African rand (R850) to R500 (from US$54.43 to US$31.97).
As of December 12, a third private laboratory company that also had been investigated, PathCare, had not agreed to the court settlement, Daily Maverick reported.
Also effective are lower prices for rapid antigen tests, the Commission said in a separate December 23 news release.
COVID Test Prices ‘Unfairly Inflated’
The changes in PCR test prices in South Africa followed a formal complaint by the Council for Medical Schemes which alleged the private pathology labs [the term for clinical laboratories in South Africa] were “supplying” COVID-19 PCR tests at “unfairly inflated, exorbitant, and/or unjustifiable” prices, Daily Maverick reported.
According to the Daily Maverick, as part of the investigation, which began in October 2021, the Commission asked the private clinical laboratory companies for financial statements and costs of COVID-19 testing.
“We did, then, further interrogation in order to strip out what we saw was potentially padding the costing and unrelated costs. And on the basis of that, we came to the figure of R500,” James Hodge, told the Daily Maverick. Hodge is Chief Economist, Economic Research Bureau, and Acting Deputy Commissioner at the Competition Commission South Africa.
For its part, Lancet, Johannesburg, said in a statement that it “Appreciates the spirit of constructive engagement with the Commission which has resulted in an outcome that best serves the people of South Africa as they confront the fourth COVID wave. We are sensitive to the plight of the public and agree that reducing the COVID-19 PCR price is in best national interest.”
Clinical Laboratory Test Prices: Market Dynamics
So, were the prices too high? In the US, clinical laboratories are reimbursed considerably more by Medicare for COVID-19 testing (about $100), as compared to the South Africa private clinical lab prices.
Also, the Centers for Medicare and Medicaid Services (CMS) said in a statement that effective January 2021 it included in that rate an incentive of $25 to labs that provide results within 48 hours.
Medical laboratories are reimbursed $75 for a high throughput COVID-19 test when results are reported beyond 48 hours, CMS added.
Antigen Tests Prices Also Reduced
The Commission said that during its review of COVID-19 PCR test pricing it received a Department of Health Republic of South Africa complaint about prices for rapid antigen test pricing as well.
After another Commission review, PathCare, Lancet, and Ampath agreed to reduce prices for rapid antigen tests to a maximum of R150 or $9.74 (from a range of R250 to R350 or $16.28 to $22.79), a news release noted.
“The reduction of COVID-19 rapid antigen test prices will help alleviate the plight of consumers and widen accessibility and affordability of COVID-19 rapid antigen testing, which is a critical part of the initiatives to avoid escalation of the pandemic,” said Bonakele in the news release, which also stated that the Commission would receive financial statements from the three labs every few months.
The Commission also is reviewing a “large retail pharmacy chain’s” rapid antigen prices, which “follows a complaint lodged by the Department of Health (DOH), on December 14 2021, against service providers delivering COVID-19 Rapid Antigen tests in South Africa to consumers,” Cape Town Etc reported. The specific pharmacy chain was not identified.
Data Show COVID Plight in South Africa
More than 21.6 million COVID-19 tests have been offered by healthcare providers in South Africa, and 3.5 million cases were detected, according to the Department of Health, Republic of South Africa.
Considering those data, one wonders if the South African government acted fast enough on test pricing.
For medical laboratory leaders, it’s important to recognize that not only are lab services in the spotlight during the COVID-19 pandemic, business practices and prices also are being monitored by officials in this country.
Nanorate sequencing allows researchers to identify changes to individual genetic sequencing letters among millions of DNA letters contained in a single cell
Detecting genetic mutations in cells requires genomic sequencing that, until now, has not been accurate enough to spot minute changes in DNA sequences. Many clinical laboratory scientists know this restricted the ability of genetic scientists to identify cancerous mutations early in individual cells.
Now, researchers at the Wellcome Sanger Institute in the United Kingdom have developed a new method of genetic sequencing that “makes it possible to more accurately investigate how genetic changes occur in human tissues,” according to Genetic Engineering and Biotechnology News (GEN).
This development suggests a new, more sensitive tool may soon be available for anatomic pathologists to speed evaluation of pre-cancerous and cancerous tissues, thereby achieving earlier detection of disease and clinical intervention.
Called Nanorate Sequencing (NanoSeq for short), the new technology enables researchers to detect genetic changes in any human tissues “with unprecedented accuracy,” according to a news release.
How Somatic Mutations Drive Cancer, Aging, and Other Diseases
NanoSeq enables the detection of new mutations in most human cells—the non-dividing cells—GEN explained, calling Wellcome Sangar Institute’s new technology a “breakthrough” in the use of duplex sequencing.
Until now, genomic sequencing has not been “accurate enough” for this level of detection, Sanger stated in the news release. Thus, there was little opportunity to enhance exploration of new mutations in the majority of human cells.
Further, the findings of the Sanger study suggest that cell division may not be the primary cause of somatic mutations (changes in the DNA sequence of a biological cell).
In their paper, the researchers discussed the importance of somatic mutations. “Somatic mutations drive the development of cancer and may contribute to aging and other diseases. Despite their importance, the difficulty of detecting mutations that are only present in single cells or small clones has limited our knowledge of somatic mutagenesis to a minority of tissues.
“Here, to overcome these limitations, we developed Nanorate Sequencing (NanoSeq), a duplex sequencing protocol with error rates of less than five errors per billion base pairs in single DNA molecules from cell populations. This rate is two orders of magnitude lower than typical somatic mutation loads, enabling the study of somatic mutations in any tissue independently of clonality,” the researchers wrote in Nature.
Refining Duplex Sequencing and Improving PCR Testing
In their study, Sanger researchers assessed duplex sequencing and found errors concentrated at DNA fragment ends. To them, this suggested “flaws” in preparation for DNA sequencing.
Duplex sequencing is an established technique “which sequences both strands of a DNA molecule to remove sequencing and polymerase chain reaction (PCR) errors,” explained a Science Advisory Board article.
Re-evaluating Mutagenesis and Cell Division with NanoSeq
It took the Sanger researchers four years to create NanoSeq. They “carefully refined” duplex sequencing methods using more specific enzymes to aid DNA cutting and bioinformatics analysis, Clinical OMICS noted.
Then, they put NanoSeq’s sensitivity to the test. They wanted to know if its low error rate meant that NanoSeq could enable study of somatic mutations in any tissue. This would be important, they noted, because genetic mutations naturally occur in cells in a range of 15 to 40 mutations per year with some changes leading to cancer.
The scientists compared the rate and pattern of mutation in both stem cells (renewing cells supplying non-dividing cells) and non-dividing cells (the majority of cells) in blood, colon, brain, and muscle tissues.
The Sanger study found:
Mutations in slowly dividing stem cells are on track with progenitor cells, which are more rapidly dividing cells.
Cell division may not be the “dominant process causing mutations in blood cells.”
Analysis of non-dividing neurons and rarely-dividing muscle cells found “mutations accumulate throughout life in cells without cell division and at a similar pace” to blood cells.
“It is often assumed that cell division is the main factor in the occurrence of somatic mutations, with a greater number of divisions creating a greater number of mutations. But our analysis found that blood cells that had divided many times more than others featured the same rates and patterns of mutation. This changes how we think about mutagenesis and suggests that other biological mechanisms besides cell divisions are key,” said Federico Abascal, PhD, First Author and Sanger Postdoctoral Fellow, in the news release.
Using NanoSeq to Scale Up Somatic Mutation Analyses
“NanoSeq will also make it easier, cheaper, and less invasive to study somatic mutation on a much larger scale. Rather than analyzing biopsies from small numbers of patients and only being able to look at stem cells or tumor tissue, now we can study samples from hundreds of patients and observe somatic mutations in any tissue,” said Inigo Martincorena, PhD, Senior Author and Sanger Group Leader, in the news release.
More research is needed before NanoSeq finds its way to diagnosing cancer by anatomic pathology groups. Still, for diagnostics professionals and clinical laboratory leaders, NanoSeq is an interesting development. It appears to be a way for scientists to see genetic changes in single cells and mutations in a handful of cells that evolve into cancerous tumors, as compared to those that do not.
The Sanger scientists plan to pursue larger follow-up NanoSeq studies.