Point of Care Testing

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Rapid blood test for rheumatism diagnostics

The term Point-of-Care-Testing or POCT for short , in German near-patient laboratory diagnostics , describes diagnostic examinations in medicine that are not carried out in a central laboratory, but in the hospital directly on the infirmary, in the practice of a resident doctor or a public pharmacy be performed. In certain situations, such as emergencies, it can also be used outside such a facility, for example in a patient's apartment or in an ambulance .

Some examinations are also intended to be used by the patient himself, for example in pregnancy tests , in coagulation self-management or in measuring blood sugar by diabetics .

In a broader sense, the term point-of-care testing is also used for corresponding diagnostic methods in other areas of application, such as in food and environmental analysis . Frequently used German terms for such examinations are on-site tests or rapid tests .

definition

There is no uniform definition of point-of-care testing . However, typical properties of near-patient chemical-physical laboratory diagnostics are:

  • Carrying out laboratory tests in the immediate vicinity of the patient, outside of a central laboratory ( bed-side testing ).
  • No sample preparation, especially no pipetting work , so the test material is mostly whole blood , urine or saliva .
  • Ready-to-use reagents, e.g. in tank or cassette form.
  • Measuring devices that are only intended for single sample measurements.
  • No detailed medical-technical training necessary for use.
  • Rapid availability of the results.
  • A diagnostic or therapeutic consequence is immediately drawn from the results.
pH indicator paper for rough pH determination; left: lid with pH scale from 1 to 11; right: stand with rolled-up test strip

Typical chemical-physical rapid tests are also used in the industrial or commercial sector, for example in

  • Checking frying fat for spoilage
  • pH value measurement using indicator strips or indicator solution additive
  • Measuring the chlorine or nitrate content in drinking water
  • Measurement of the exhaust gas proportions of CO and hydrocarbons after boilers and in motor vehicles

advantages

Device for performing blood gas analyzes

Point-of-care examinations have the advantage that the results are available after a short time, because on the one hand, the samples do not have to be transported to a specialized laboratory and, on the other hand, there is no need to take account of the laboratory's temporal processes. The so-called turn-around-time (TAT), i.e. the time that elapses before the result is available, is often between 5 and 15 minutes. It is thus well below the TAT that can be achieved in the central laboratory even under optimal conditions .

This time advantage is particularly important in areas in which decisions must be made quickly on the basis of laboratory values. This is why POCT is mainly used in intensive care units and in anesthesia , but also in outpatient departments or in dialysis . As a rule, these are so-called emergency parameters such as electrolytes , blood gas and blood clotting values , kidney function values, heart enzymes and other measured values. But also urine tests, the creation of a blood count or the quick detection of pathogens or autoimmune diseases such as rheumatoid arthritis are possible with the help of point-of-care methods.

Many point-of-care examinations are designed as test strips, which reduces the manual effort involved in performing them to a minimum. Measuring devices for point-of-care use are usually almost completely automated and require only a few simple interventions on the part of the user, from sample preparation to the test result.

restrictions

The main disadvantages of point-of-care tests are the higher reagent costs and the often method-related lower analytical sensitivity (sensitivity) and specificity (accuracy). The sample throughput is also usually significantly lower than with corresponding laboratory methods. In addition, corresponding quick test methods are only available for some parameters.

See also

Individual evidence

  1. ↑ Luppa and Schlebusch 2008, p. 16
  2. ↑ Stürenburg E, Junker R .: Point-of-care testing in microbiology: the advantages and disadvantages of immunochromatographic test strips. . In: Dtsch Arztebl Int. 2009 Jan; 106 (4): 48-54. . August. PMID 19564967 .
  3. ↑ Egerer K, Feist E, Burmester GR .: The serological diagnosis of rheumatoid arthritis: antibodies to citrullinated antigens. . In: Dtsch Arztebl Int. 2009 Mar; 106 (10): 159-63. . August. PMID 19578391 .

literature