Point-of-care testing (POCT): Current techniques and future perspectives

Abstract

Point-of-care testing (POCT) is a laboratory-medicine discipline that is evolving rapidly in analytical scope and clinical application. In this review, we first describe the state of the art of medical-laboratory tests that can be performed near the patient. At present, POCT ranges from basic blood-glucose measurement to complex viscoelastic coagulation assays. POCT shortens the time to clinical decision-making about additional testing or therapy, as delays are no longer caused by transport and preparation of clinical samples, and biochemical-test results are rapidly available at the point of care. Improved medical outcome and lower costs may ensue. Recent, evolving technological advances enable the development of novel POCT instruments. We review the underlying analytical techniques. If new instruments are not yet in practical use, it is often hard to decide whether the underlying analytical principle has real advantage over former methods. However, future utilization of POCT also depends on health-care trends and new areas of application. But, even today, it can be assumed that, for certain applications, near-patient testing is a useful complement to conventional laboratory analyses.

Keywords: Bench-top POCT analyzer; Continuous measurement POCT system; Hemostaseological coagulation analyzer; Molecular-biology-based POCT device; POCT; POCT data-manager software; POCT in developing countries; Point-of-care testing; Strip-based POCT; Unit-use analyzer.

Figure 1

The biosensor as the basis of analysis in many point-of-care testing (POCT) instruments. Note that the recognition layer may comprise attached recognition elements (antibodies, receptors, aptamers …) or immobilized enzymes. In the latter case, the addition of substrates is essential. Not illustrated is the fact that the amplified signal is finally processed by microelectronics and displayed.

Figure 2

The principle of microdialysis for measuring analyte levels in the subcutaneous tissue. This “alternate-site monitoring” implicates divergent concentrations compared with blood/plasma.

Figure 3

The principle of colorimetric detection of nucleic-acid sequences. When single-stranded DNA-modified gold nanoparticles are attached to a glass slide and white light is coupled into the glass chip (Step A), the evanescent induced scatter is observed. The non-hybridized gold nanoparticles scatter with h × ν₁. Step B: the DNA probes are hybridized to a DNA target in solution. When they are spotted onto the glass slide (Step C) these hybridized gold nanoparticles scatter with h × ν₂. The plasmon efffect induces a red light shift with ν₂ < ν₁. The scheme presented is in accordance with .

Figure 4

Preventative medicine via early detection of chronic disease (e.g., the multigenetic diseases arteriosclerosis or diabetes mellitus type 2) with the help of simple-to-use point-of-care testing (POCT) methods.