Multiplexed point-of-care testing

Multiplexed point-of-care testing (xPOCT) is the simultaneous on-site quantification of various analytes from a single sample (e.g., blood, plasma or urine). Derived from emerging applications in resource-limited settings, (e.g., in the developing countries, in doctor's practices, or at home) xPOCT has recently become more important for in vitro diagnostics.^[1]

Requirements

xPOCT devices has to completely fulfill the following demands:^[1][2]

• Low sample consumption (e.g., blood from a finger prick) or the ability to measure in noninvasive samples (e.g., saliva, urine or exhaled breath condensate)
• Fast sample-to-result times enabling an immediate treatment
• Long shelf life with extended reagent storage
• Comparable test results with central laboratory findings ensuring international quality standards (ISO 15189)
• Automatic or facile system operation with minimized user intervention
• Cheap and portable readout systems (e.g., handheld readers) along with disposable test strips or cartridges fulfilling the in vitro diagnostics guideline (EU Directives or FDA regulations).

Especially for the resource-poor settings, equipment-free or smartphone-based devices are very advantageous.^[3] Besides, an ideal xPOCT device should be capable of testing various kinds of substances, including proteins, drugs, RNAs and cells, at the same time.

Current multiplexing technologies

Nowadays, multianalyte detection is mostly achieved through three different approaches:

1. Regional separation employing distinct sections of a channel network or array of electrodes
2. Spatial separation of detection sites with the help of various wells or spots
3. Application of multiple labels such as enzymes, redox molecules, beads, and dyes

For the signal readout, optical and electrochemical detection methods are mainly employed.^[4][5]

References

1. 1 2 Dincer, Can; Bruch, Richard; Kling, André; Dittrich, Petra S.; Urban, Gerald A. "Multiplexed Point-of-Care Testing – xPOCT". Trends in Biotechnology. 0 (0). ISSN 0167-7799. doi:10.1016/j.tibtech.2017.03.013. 
2. ↑ Gauglitz, Günter (2014-01-01). "Point-of-care platforms". Annual Review of Analytical Chemistry (Palo Alto, Calif.). 7: 297–315. ISSN 1936-1335. PMID 25014344. doi:10.1146/annurev-anchem-071213-020332. 
3. ↑ Vashist, Sandeep Kumar; Luppa, Peter B.; Yeo, Leslie Y.; Ozcan, Aydogan; Luong, John H. T. (2015-11-01). "Emerging Technologies for Next-Generation Point-of-Care Testing". Trends in Biotechnology. 33 (11): 692–705. ISSN 0167-7799. doi:10.1016/j.tibtech.2015.09.001. 
4. ↑ Araz, M. Kursad; Tentori, Augusto M.; Herr, Amy E. (2013-06-11). "Microfluidic Multiplexing in Bioanalyses". Journal of Laboratory Automation. 18 (5): 350–366. doi:10.1177/2211068213491408. 
5. ↑ Rusling, James F. (2013-06-04). "Multiplexed Electrochemical Protein Detection and Translation to Personalized Cancer Diagnostics". Analytical Chemistry. 85 (11): 5304–5310. ISSN 0003-2700. PMC 3674208 . PMID 23635325. doi:10.1021/ac401058v.