Why qPCR & Phenotypic Testing Must Be Displaced? โ Part III This is the third part of a deep dive into why qPCR & phenotypic testing need to be replaced. In Part I, I covered the limitations of current diagnostics & why incremental improvements arenโt enough. Part II looked at targeted Next-Gen Sequencing (tNGS) as a potential solutionโcapable of identifying both pathogens & resistance in a single test. But if tNGS is going to work in clinical settings, it needs to be as simple as qPCR. Right now, itโs not. The biggest obstacle isnโt sequencingโitโs automation. Thatโs what Iโm tackling in Part III. The Challenge of Automating Sequencing for Clinical Use If you need molecular diagnostics in a hospital, you use qPCR. Itโs fast, simple, & has been the standard for decades. Cepheid has been around for 26 years, with 40,000 GeneXpert instruments installed & $2 billion in revenue. Their system works because itโs designed for clinicians, not lab scientistsโdrop in a sample, press a button, & get results. No complex prep, no custom protocols. Cepheid isnโt the only player anymore. Indian company Molbio Diagnostics has taken a similar approach. Their Truenat system is a real-time RT-PCR platform designed for low-resource settings. Itโs already deployed in ~8,000 hospitals & clinics globally. More importantly, the cost per test is competitiveโ$7.90 per sample, similar to Cepheidโs $8 cartridges. Itโs clear that automation works when the workflow is simple. Truenat, like GeneXpert, is built around one test, one result, one action. No batching, no custom protocols, no flexibility. Thatโs why it succeeds in clinical settings. Why Isnโt Sequencing as Simple as qPCR? Sequencing is messy. Itโs not just about running a machineโitโs about sample prep, library prep, sequencing, & analysis. Each step requires specialised reagents, workflows, and trained personnel. Thatโs why sequencing is still mostly confined to research labs & high-end clinical centres. Itโs powerful, but not simple. People have tried to automate sequencing workflows. Pipette robots are one approach. These are flexible and can automate parts of the process, but they require maintenance, trained staff, and custom protocols. They donโt eliminate complexityโthey just shift it. Instead of pipetting by hand, you program the robot to pipette for you. Full automation still isnโt plug-and-play. Another approach is closed-box automationโmachines like MagicPrep NGS that handle everything for you, as long as you use their kits and follow their protocol. It works, but locks users into fixed workflows. Need to change anythingโmultiplexing, target selection? Youโre out of luck. Then there are digital fluidics platforms like Illuminaโs NeoPrep or ONTโs Voltrax. These miniaturise reactions into a microfluidic chipโelegant in theory but expensive and rarely adopted. One of the newest attempts to tackle this problem is Volta Labsโ Callisto System. Instead of pipettes or cartridges, Callisto uses electrowetting-based digital fluidicsโtiny droplets move around a chip, performing DNA extraction and library preparation without physical pipetting. Itโs a brilliant idea. But itโs still a $125,000 benchtop instrument, which makes it out of reach for most hospitals and small labs. Itโs automation, but not yet clinical automation. Meanwhile, Cepheid and Molbio still dominate clinical molecular diagnostics with their simple, cartridge-based qPCR systems. Why Not Just Build a Sequencing Cartridge Like Cepheid? Technically, thereโs nothing stopping someone from making a cheap, plastic, preloaded reagent cartridge that automates sequencing prep. But the problem isnโt technicalโitโs demand. The whole reason sequencing is powerful is its flexibility. Labs want to run different assays, multiplex samples, and tweak protocols. A single-use cartridge locks them into a fixed workflow they donโt want. Thatโs why no one has built a sequencing equivalent of Cepheidโs GeneXpertโit would be a niche product at best. The real problem isnโt the lack of automation. Itโs that sequencing users donโt want the kind of automation qPCR users need. Where Does That Leave Us? Thereโs still room for improvement. The transition from manual prep to automated sequencing isnโt fully solved. The right solution probably isnโt a single cartridge system but something modularโautomating the most painful parts while keeping flexibility where itโs needed. Maybe that means hybrid systems that allow some customisation. Maybe it means smarter automation that adapts protocols based on sample type. But if weโre looking for a one-size-fits-all, push-button sequencing solution, we may be searching for something that clinicians donโt actually want, and sequencing labs donโt actually need. Thatโs why automation in sequencing isnโt a solved problem. Not because itโs too hard, but because itโs not clear what problem needs to be solved. Letโs Talk. Drop a comment or DM meโletโs figure this out together. ๐
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