Point-of-Care HIV Diagnostics for Low Resource Regions: Interview with Jesse Lehga, VP at Diagnostics for the Real World

By | February 28, 2020

DRW (Diagnostics for the Real World), a company with headquarters in San Jose, California, and Cambridge, United Kingdom, has developed the SAMBA II, a point-of-care diagnostic device for the detection of infectious diseases, including HIV and HCV, for use in low-resource and/or remote regions. The system employs nucleic acid amplification to detect viral RNA or DNA in whole blood or plasma samples.

The technology involves easy-to-use test cartridges, containing all the required consumables for each assay, that a user can insert into the portable SAMBA device. The cartridges do not require cold storage, are easy and inexpensive to transport and store, and are single-use and completely sealed, which reduces the chances of contamination. The assay module connects with a tablet computer through Bluetooth, and the tablet allows a user to control the device and read the results. The tablet can also transmit the results to clinicians based elsewhere through Wi-Fi or text messages.

This point-of-care system is fully automated, allowing people with minimal training to use it, and requires less than 1 minute of hands-on time per assay. The device is also robust, working in a wide range of temperature conditions (10–38 degrees Celsius), permitting deployment in a huge array of environments.

A back-up battery power supply means that the SAMBA can run assays even if there are intermittent power outages, which means no interruption of usage. This is particularly useful in low-resource regions, as access to power can frequently be unreliable in such areas.

Medgadget had the opportunity to talk to Jesse Lehga, the V.P. of Operations & Business Development for DRW, about the technology.

Conn Hastings, Medgadget: Please give us an overview of the need for infectious disease testing, such as HIV testing, at the point of care (POC).

Jesse Lehga, DRW: Winning the battle against HIV and other infectious diseases is always a matter of how well diagnostics and treatment are adapted to local conditions. In resource-limited settings, the requirements for prompt, efficient and reliable disease management are numerous and challenging. Since centralized diagnostic machines require considerable bench space, air conditioning and trained personnel, these instruments are often only available in large cities, making them inaccessible to patients in rural areas.

As a result, diagnosis and treatment is delayed for those who need it most, and patients often get lost in the system due to the delayed turnaround time for results. There are also additional logistical issues related to sample collection, transportation, testing and delivery of the results, further adding complexity to the equation. The clear solution is to decentralize testing, which enables direct sample collection and diagnosis at the POC where patients are seen, so that prompt clinical intervention and treatment can be initiated immediately.

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In the case of HIV specifically, because the HIV virus can occasionally change or mutate to become resistant to the drug being used, repeat testing must be carried out. Due to this, it is important to closely monitor the viral load of positive patients to ensure that switching to another effective drug is completed in a timely manner. Viral load testing, which can be performed at the POC with SAMBA, allows for treatment failure to be closely monitored, but with the long turnaround times for test results in under-resourced or rural areas, it can be extremely challenging to quickly switch to another effective drug, should the virus mutate. And of course, HIV isn’t the only infectious disease for which early intervention can be critical to effective treatment, which is why DRW is committed to expanding our test menu to cover more infectious agents, with hepatitis B and C tests expected to be released in 2020 and other tests including influenza A and B, and other sexually-transmitted infections in development.

Medgadget: What unique challenges do low-resource regions pose for diagnostic devices, and healthcare generally?  

Jesse Lehga: There are several challenges that low resource regions pose, including the unreliability of previous simple point-of-care technologies, and the prohibitive costs and logistical difficulties associated with central laboratory testing. With a centralized testing system, the number of people living with HIV who accessed viral load testing stood at 15 percent, because of the lack of reliable, prompt diagnosis and monitoring.

Many of the rural clinics that patients can access most easily are not equipped with much equipment, and lack the highly complex viral load testing machines that are required. As a result, blood samples must be transported to another hospital, and sometimes then on to yet another, and still another, by the time it makes it to a testing queue, which means that the turnaround time for results can be as long as six weeks or more.

Making this centralized system even more challenging, in some regions, is the fact that fuel shortages and electricity blackouts make it difficult, if not impossible, for samples to be transported to centralized testing labs. Often, the labs themselves suffer from issues like lack of air conditioning or electricity supply to run these large and complicated testing machines.

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Medgadget: How does the SAMBA device work? How is it tailored for low-resource environments?

Jesse Lehga: DRW’s SAMBA (Simple AMplification Based Assay) system is an innovative high-tech nucleic acid-based test for the diagnosis of infectious diseases. With while-you-wait results, SAMBA enables test and treat clinics to make prompt and effective clinical decisions.

SAMBA is delivered through two systems: SAMBA I and SAMBA II. SAMBA I is a high-throughput semi-automated system, ideal for district or regional hospitals. SAMBA II is a fully automated system for diagnosis and treatment monitoring at the point of care. SAMBA I and SAMBA II use the same proven chemistry for accurate and fast qualitative or semi-quantitative detection of infectious agents with no toxic waste. The SAMBA platforms offer the widest operating temperature range available, allowing fast and accurate diagnosis and treatment monitoring at, or near, the point of care. They are manufactured to exacting standards, making them the reliable option even in remote clinics in resource-limited settings.

Importantly, SAMBA II eliminates the need to collect blood from the veins of patients, which not only requires a trained nurse but also the removal of white and red blood cells by centrifuging the sample. Of course, many rural clinics are not equipped with centrifuges – they’re expensive and require maintenance and calibration.

Instead, a drop of blood can be simply collected by a finger prick in adults or a heel prick in babies. The sample is placed directly into the portable SAMBA machine, the size of an at-home coffee maker, and in less than 90 minutes, the results are out.

Turnaround time for results goes from several weeks to same-day, which allows clinicians to promptly make decisions without having to ask patients to return at a later date when the results become available.

Medgadget: Are the diagnostic results comparable with those from a lab-based test, in terms of accuracy and sensitivity?

Jesse Lehga: The currently available SAMBA assays are the HIV-1 Qualitative Whole Blood Test, HIV-1 Semi-Quantitative Plasma Test, and the HIV-1 Semi-Quantitative Whole Blood Test, which all show a high concordance with centralized testing as well as high sensitivity and specificity (>95%). The HCV Qualitative Whole Blood Tests is undergoing trials and is expected to receive regulatory approval in just a few months.

The SAMBA assays are nucleic acid-based tests, allowing earlier detection than even the 4th generation immunoassays. This makes the qualitative the ideal choice to aid in early infant diagnosis (EID) or acute infection diagnosis at the point of care. Early HIV and HCV infection during the “window” period may be incorrectly diagnosed by immunoassays as proteins and/or antibodies are not yet detectable.

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The semi-quantitative tests use either a whole blood or plasma sample, and are intended for use with antiretroviral therapy (ART) monitoring. The test accurately determines if the patient has a viral load of greater than or less than 1000 copies/mL.

Medgadget: How has the device been received by healthcare workers so far?

Jesse Lehga: The response has been very positive, as healthcare workers recognize the potential for impact with POC testing. Several hundred thousand patients have been tested by either SAMBA or SAMBA II, and the clinicians find the instrument system very reliable and easy to use. There is very little training needed to run the machines and our support staff in the field is quick to respond in the rare case that service is needed.

Medgadget: DRW has recently partnered with Bright Machines, a manufacturing startup, to increase production of the test cartridges used in the SAMBA. How will this increase the reach and influence of this technology?

Jesse Lehga: DRW will now use a Bright Machines Microfactory to automate the California-based manufacturing of the complex test cartridges used in the SAMBA II diagnostics device. This automation will free our team from repetitive, labor-intensive assembly and inspection tasks while increasing output of these care-critical cartridges by more than 10 times, to more than 1 million units a year. Specifically, the microfactory will decrease headcount from seven people to one to two people per cartridge, reducing assembly time from two minutes to just 20 seconds per unit, and increase our overall yield significantly from 100,000 units a year to one million units a year. The macro impact of course is increased affordability and availability of our advanced diagnostics technology, which a growing number of clinics around the world have come to rely on for fast, accurate diagnosis and disease management. With the increased output, we expect to reach even more healthcare providers.

This ability to dramatically scale manufacturing means we’ll be better able to meet the demands for test cartridges, which will impact the lives of millions of people who otherwise wouldn’t have access to centralized testing. Producing more SAMBA test cartridges at a faster rate, while also saving on labor costs, will also directly impact the end-user price of our advanced diagnostics technology, making our tests even more affordable and accessible. It’s a great example of how technology and automation can solve big, real-world problems.

Link: DRW homepage…


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