qPCR? dPCR? From Anywhere? They’ve Got an App for That in Infectious Disease Testing

qPCR? dPCR? From Anywhere? They’ve Got an App for That in Infectious Disease Testing

This blog post reviews molecular point-of-care (POC) diagnostic platforms included in the most recent edition of the reportThe Market and Potential for Molecular Point of Care Diagnostics. Kalorama Information offers related titles withqPCR and dPCR Markets,The World Market for Infectious Disease Diagnostic Tests, andThe World Market for Molecular Diagnostics.

Make sure to visit our Point of Care Testing page, Kalorama's all-in-one resource covering the POC testing market. 

Contributing a high amount of growth to the clinical IVD market over the past decade, molecular diagnostics is established in reference labs, increasingly common among hospital labs, and an emerging solution at clinical points of care. The capabilities of molecular diagnostics at each level of care are also growing: clinical next-generation sequencing (NGS) is available from reference labs, hospital labs can send out fewer tests thanks to expanding assay menus on platforms such as the GeneXpert, and now many IVD companies are on the cusp of introducing routine quantitative molecular testing outside of the lab.

Each stage of diffusion in clinical molecular testing encounters fewer users with lab resources or experience in molecular diagnostics procedures. The problem is particularly acute among CLIA-waived sites in the United States and in large parts of the developing world. To alleviate these demands, test procedures are integrated and automated within the instrument. The resulting instruments are often costly or at least beyond the financial resources of decentralized testers, particularly those in resource-limited countries. However, several molecular point-of-care (POC) diagnostic platforms and technologies are taking advantage of the seeming ubiquity of another resource: smartphones.

The average smartphone now possesses the processing power necessary for a variety of applications (apps) and can even be enlisted to interpret complex quantitative molecular test results like from qPCR. In addition to data processing, smartphones also incorporate components necessary in most clinical analyzers - cameras for optical detection and connectivity for sharing of results.

Several companies in the molecular POC diagnostics space have developed smartphone-based testing platforms:

  • Cepheid - In July 2015, Cepheid unveiled the GeneXpert Omni, a portable qPCR system for HIV, TB and Ebola testing in remote and developing regions. The system stands at just over 9 inches tall, weighs roughly 2 pounds and can run the same Xpert cartridge tests used with existing GeneXpert systems. The GeneXpert Omni is battery-operated, wireless and web-enabled to transmit results in real-time for public health screening and mobile clinic applications. The instrument will use a smartphone interface for operation and the display of results.
  • Biomeme - The heart of Biomeme’s device is the Arduino open-source electronics prototyping platform that can adjust PCR reaction temperature with heaters and fans. The device also controls excitation light and the wireless connection of the iOS device or iPhone 5S. A separately sold sample preparation kit contains test tubes and freeze-dried reagents for the performance of qPCR tests from saliva, blood, or urine samples. Fluorophore probes included in Biomeme test kits are detected by the smartphone camera to monitor reactions in real-time. After a 40-minute run, the smartphone processor is used to perform algorithms based on the optical data. The wireless or cellular connection of the phone GPS tags results and sends them to cloud storage. The open-source Arduino platform is also compatible with isothermal LAMP protocols.
  • Ubiquitome - The company developed the Freedom4 portable, cloud-connected, battery-powered qPCR device for distributed and field testing for research, applied, and clinical markets. The instrument can operate for 6 hours on battery power and is operated using an iPhone or laptop computer. The Freedom4 features a 4-well block for up to 4 samples of 10-40 μL each and is compatible with SYBR green dye. Run time for 30 qPCR cycles is 50 minutes with detection provided by a laser diode and photodiode array (PDA). The instrument weighs approximately 5 pounds and measures roughly 8 x 4 x 3 inches.
  • Diagnostics for the Real World (DRW) - The SAMBA II system is fully automated with sample extraction, amplification and test detection all performed within one module. A separate display module provides touchscreen control and displays results. Alternatively, a phone module can be used to control up to two assay modules. The SAMBA II offers throughput of 4-32 samples a day. The system can also perform random access testing. Results can be read visually due to the cartridges’ lateral flow format. Colored anti-haptens result in the chromatographic change that can be read by the instrument or user within 25 minutes. Total turnaround time for the SAMBA EID HIV test is approximately 2 hours.
  • DiAssess - At the Y Combinator Demo Day held in March 2015 in Silicon Valley, DiAssess exhibited its new NAAT system capable of performing rapid infectious disease testing in less than 20 minutes, at a cost under $10, and completed in 3 simple steps from urine or saliva samples. The handheld device can also be linked to a smartphone for results communication.

Researchers with the California Institute of Technology (CalTech) are also working to bring highly sensitive quantitative molecular testing from the lab into the field. Utilizing the in-house-developed SlipChip lab-on-a-chip (LOC) technology, the CalTech-developed test isolates single molecules of nucleic acid target in nanoliter volumes across a population of hundreds or thousands of wells. Within each well, the single target molecule is isothermally amplified (if present) and creates a colorimetric change with amplification-indicator dyes. Each reactive or color-changed well represents one unit of quantity for the sample target. The entire population of reactive and non-reactive wells is then imaged with an app-enabled smartphone and each reactive well counted. Comparable to laboratory-performed digital PCR results (dPCR), the CalTech smartphone-LOC technology could be used in practically any setting with robust isothermal amplification methods such as LAMP to perform HIV and hepatitis C viral load testing for patients receiving antiviral therapy.

Resource-limited areas of the developing world are in desperate need of near-patient quantitative molecular results. Major global initiatives for disease control are expected to shift from expansive screening efforts to treatment as affected populations are diagnosed. In the upcoming report The Market and Potential for Molecular Point of Care Diagnostics, Kalorama Information provides market projections in 2020 for molecular POC diagnostics in HIV and HCV patient monitoring. While break-through platforms for universal molecular diagnostics accessibility are a work in progress, half the solution may already be in the grasp of users worldwide.