Poct Disadvantages: Samples, Reagent Storage, Quality Control

release time:2021-09-14 10:23:35

POCT test is a new direction. In its emergence and development, there are many areas for improvement. Such as quality control, varying levels of operator skill and clinical management is not perfect.

Hospitals should incorporate POCT test into their overall management system. To improve the accuracy of point-of-care testing and effectively achieve comprehensive quality control of point-of-care testing, so that its results can more effectively guide clinical diagnosis and treatment.

POCT test has 6 main drawbacks. We are divided into Part 1 and Part 2 to introduce them.

Part 1

The following aspects should be noted in the quality control of POCT test.

1. POCT test Specimen collection and patient preparation

Clinical tests have specific requirements for test specimens. For example, the type of specimen anticoagulant type. The operator must be clear about what the patient should be aware of or contraindicated before being tested. This is a prerequisite to ensure the reasonableness of the test.

The first step is to understand what specific requirements for specimens in the test principle. For example.
a) most optical test instruments will be subject to interference from hemolysis and celiac disease in the specimen.
b) Chemiluminescence development method will be affected by exogenous redox substances.
c) The patient whose blood is to be taken should be in a calm state of fasting. Satiety and fatty foods can interfere with the determination of platelet factor and fibrinolytic components.
d) Patient stress and vigorous exercise will also cause bias in the measurement.
e) It is important to ensure that the specimen is fresh and to verify that the patient is not taking medication.
f) Diuretics can lead to false-positive nitrite test tests.
g) Urine contaminated with formaldehyde, etc., can cause false positive leukocyte tests.
h) Differences in hematocrit may lead to differences in the determination of whole blood glucose levels.
i) differences in enzymes (oxidases, dehydrogenases, several glycosylases) in reagents may be further reflected between methodologies.
j) Even differences in oxygen content between capillaries, veins and arteries may affect the results of some POCT test instruments.

2. POCT test Reagent storage and use

Various reagent strips and instruments based on immunochromatographic, chromatographic and dry chemistry techniques can affect the activity of microproteins in the reaction matrix depending on temperature, humidity and pH. This in turn affects the results. Therefore, special attention needs to be paid to the drying of the reagent strips. The reagent strips should be used as they are taken. Do not expose them to air for a long time to prevent moisture or contamination of the test strips. Analyzers based on magnetic field changes should avoid magnetization of the iron powder in the reflector card. Experiments using test tubes as test carriers should pay attention to the activity and expiration date of activators or anticoagulants, etc. in the tubes.

3. POCT test Instrument calibration and quality control

POCT test instrument quality control

Humid air attached to the instrument optical path system will affect the results. Therefore, instruments for optical principle detection (such as optical biosensors) measuring glucose, electrolytes or arterial blood gases should be stored dry.

Adhere to quality control for POCT test instruments to determine if the instrument appears abnormal during use. Plot QC using quality controls provided by the POCT instrument manufacturer. And perform statistical analysis of QC plots.

Calibration of POCT test instruments

In principle, POCT test instruments are calibrated at least once a week. For example, with a portable hemagglutinator, not only should the instrument be subjected to daily indoor QC with normal and abnormal plasma provided by the instrument manufacturer. Inter-room QC is also performed monthly with fresh venous plasma between similar instruments with identical methodologies and close reagents. Instrument custodians and self-monitoring patients should be familiar with the performance and storage conditions of the instruments.

The other 3 shortcomings of the POCT test will be described in this article. Poct Disadvantages: Training, Reporting, Regulations

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