Point-of-care testing (PoCT) is now found in all kinds of settings such as hospital bedside, home, health clinic, ambulatory service, diagnostic, and research laboratory. The scope of testing varies from glucose, ABG analysis, drug of abuse, hematology, coagulation testing kits, cardiac markers to genetic testing. The World Health Organization (WHO) has provided the ASSURED criterion, which stands for affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free, and deliverable; and PoCT classically fits in this definition for in vitro diagnostics particularly for limited resource settings. PoCT offers remarkable advantages over central laboratory testing of specimen usually done through finger prick and can be handled by staff not trained in laboratory procedures; non-transportation of sample reduces or improves TAT (5–15 min). The PoC instrument is connected to HIS (hospital information system) hence the data is transferred and values beyond reference intervals including critical ones are highlighted.
Emerging technology trends
Lab-on-a chip device. LoC is a device that integrates one or several laboratory functions on a single integrated circuit of only millimeters to few square centimeters. Miniaturization has multiple advantages including small sample volume, reduced volume of reagent, low power consumption, parallel analysis and functional integration of multiple devices, improved TAT, improved accuracy as well as precision.
Microfluidic paper-based analytical devices. µPAD is an innovative analytical device fabricated by printing toner on the top and bottom using a laser printer. It has paper-based microfluidic channels, which use capillary action and by patterning of paper control transport of fluids. The advantages include easier reproducibility, low limit of detection, inexpensive, portability making it easy-to-use, and no requirement of external equipment. Microfluidics is an attractive technology for PoC immunoassays, for example, HIV.
Cell phone based assays. Slip chip technology and camera phone are used to read out the results.
In future there will be great demand for XPoCT (multiplexed) to simultaneously screen various analytes, driven by novel bio technologies (e.g., aptameters, i.e., nucleic acid molecules binding to non-nucleic molecules) or nano sensors or targets (e.g., circulating tumor cells). This will enable a rapid, low-cost, and reliable quantification from the same sample. The present trend is inclined toward smart phone based PoC diagnostic technologies. Recently there was news of a first version of a mobile ELISA enabled rapid PoC instrument from South Florida. Further research is necessary to analyze the potential contribution of PoCT in reducing the healthcare costs in total and empowering the patient in the personal care pathway.
The question that arises is whether PoCT will be able to replace the present laboratory diagnostic system completely? Unlikely. LoC is promising low cost devices for future if it covers a vast spectrum of disease. It needs to be brought into commercial use rather than remain a research tool as at present. But it has its own challenges as it needs to incorporate more advanced technology, be more organized. Also the role of central laboratory and reference lab for complex tests cannot be underestimated.