In The Laboratory: Quality Assurance

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In The Laboratory: Quality Assurance
In The Laboratory: Quality Assurance

Video: In The Laboratory: Quality Assurance

Video: In The Laboratory: Quality Assurance
Video: Quality Management System, Quality Assurance, and Quality Control in the Laboratory 2023, March

In the laboratory: quality assurance

The most important factor in the creation of laboratory measurements is the quality of the test result. In particular, the analytical quality comes first. Because the goal is correct and precise laboratory results.

For this reason, the most complete possible knowledge of possible sources of error that exist in the context of the entire diagnostic process is paramount in order to avoid potential errors in general. Sources of error do not only exist within the medical laboratory, but can also occur when the blood is drawn (e.g. a sample mix-up due to incorrectly taping the blood collection tube).

All these errors are subsumed under the term “preanalytics” and can lead to incorrect results with potentially dangerous consequences for the affected patient despite the analytical accuracy and precision of the laboratory diagnostics.


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  • What does quality mean in laboratory diagnostics?
  • The laboratory should work quickly and economically
  • The goal is correct and precise laboratory values
  • What is meant by round robin tests?
  • The "gold standard" of a laboratory method
  • How can quality be measured?
  • What does a quality certificate mean?

What does quality mean in laboratory diagnostics?

Quality is of great importance in healthcare. In medical laboratory diagnostics, “quality” is the daily bread of all laboratory employees. In this specialty of medicine, this is due to the fact that measured values are constantly being generated. For this reason, the measurement methods used in the laboratory also have to pass a series of tests every day. The laboratory procedures must

  • calibrated (called "calibration") and
  • be tested for correctness and precision ("quality control").

The laboratory should work quickly and economically

In addition to the accuracy and precision of the laboratory values, there are a number of other criteria that play a role in the quality of the medical laboratory work.

The medical laboratory has to work quickly:

  • In hospitals in particular, vital laboratory values must be available within a very short time:

    • Blood count, blood coagulation and blood group examinations for urgent operations,
    • Laboratory values for the heart, kidneys, inflammation and much more for quick therapy decisions.

The medical laboratory must work economically:

  • In the medical laboratory, exact cost accounting is always carried out so that the resources used are used as best as possible and as sparingly as possible for our health system.
  • Medical laboratories are often networked, especially in the hospital sector (e.g. in the hospital group of the municipality of Vienna or in the Vinzenz group). This can avoid unnecessary duplicate examinations. For example, a patient's blood group would only have to be determined once in a lifetime, because the blood group does not change throughout life.

The goal is correct and precise laboratory values

When looking at the numerical values on a laboratory result, some patients, but often also some doctors, ask themselves the question: Are these laboratory values really correct?

This question is easy to answer for the laboratory doctor - provided that no mistakes were made during the blood sample. That means:

  • a correct preanalytics and
  • no mix-up of blood samples.

Because the laboratory doctor knows that with regard to the laboratory measurement procedures used in the medical laboratory, every laboratory test runs through an exact daily test program with regard to accuracy and precision.

© Dr. Gerhard Weigl

© Dr. Gerhard Weigl

What is meant by round robin tests?

All laboratory tests are checked daily in the medical laboratory. In technical jargon this is called precision control and accuracy control. In addition, every medical laboratory in Austria must also take part in round-robin tests (also called "round robin tests" or "external quality control"). These round robin tests take place several times a year and meanwhile concern almost all laboratory analyzes.

In a round-robin test, each laboratory receives an unknown sample and has to treat this sample in the same way as a test material from a patient by collecting the laboratory values to be examined (according to the round-robin test protocol). The results of the round-robin test samples are then transmitted to the round-robin test leader and evaluated accordingly.

If the medical laboratory in question passes the round-robin test in terms of accuracy and precision, the laboratory receives a round-robin test certificate for the corresponding test. This is valid until the end of the next round-robin test.

In Austria, the implementation and evaluation of the round robin tests is coordinated by the "Austrian Society for Quality Assurance and Standardization of Medical-Diagnostic Examinations". You can find more information on the homepage

The "gold standard" of a laboratory method

A big question in medical laboratory diagnostics is who says what is right?

Because even with the round-robin tests, it must be ensured that the corresponding target values of the round-robin samples (these are the values that should be found by the laboratories participating in the round-robin test) are really correct.

For this reason, there is a so-called gold standard for almost all laboratory tests. This is understood to be an impeccable laboratory method (also called “reference method”). Such methods are sometimes technically complex and expensive, and therefore simpler methods are often used in medical laboratories: so-called "routine methods".

To compare gold standard and routine methods, there are indicators in laboratory medicine for the diagnostic quality of the laboratory tests used. These key figures include, for example:

  • The diagnostic sensitivity of a laboratory test: This is the measure of the ability of a laboratory test to show a really positive result if the patient is actually ill.
  • The diagnostic specificity of a laboratory test: This is the measure of the ability of a laboratory test to give a true negative result when the patient is actually healthy.

How can quality be measured?

In the medical laboratory, the quality is assessed, recorded and ensured on various levels. For this purpose, the quality is divided into the following areas:

  • Structural quality

    • Laboratory equipment (ventilation technology, air conditioning, shading, etc.),
    • modern laboratory equipment (laboratory equipment, microscopes, computers and laboratory information system, etc.),
    • qualified laboratory employees.
  • Process quality

    • Selection of laboratory tests with appropriate accuracy and precision,
    • Implementation and recording of daily quality controls (accuracy and precision controls).
  • Result quality

    • Successful participation in round robin tests,
    • Checking the laboratory results for plausibility: The "transversal assessment" checks whether the laboratory values match a patient's finding. The "longitudinal assessment" checks whether the laboratory values of a patient match with existing laboratory values.

Appropriate records are kept in the laboratory to record and measure quality in the areas of structure, process and result quality. Laboratory specialists must, for example, have a valid advanced training diploma from the Medical Association. The same applies to other groups of laboratory staff (e.g. biomedical analysts).

In addition, so-called key figures are defined for some laboratory areas, which can be used to assess the qualitative performance of the laboratory. Such key figures include the number of repeated measurements, the weight of biological waste, the added value of the employees and much more

What does a quality certificate mean?

As already mentioned, “quality” is a complex term. For this reason, a special procedure is required, especially in a medical laboratory, in order to guarantee the quality of the laboratory at all levels. Such a procedure is known as a quality management system (QMS).

A QMS should ensure that the processes used in the medical laboratory are constantly checked and, if necessary, also improved. The aim of a QMS in the medical laboratory is to permanently ensure or, if necessary, improve the quality of the services of a medical laboratory: correct, precise and plausible laboratory values.

To comply with the standards of a QMS, the certification of the QMS according to certain industrial standards has proven itself. One of the best-known industrial standards is the quality management standard according to ISO 9000, 9001 and 15189. These standards have also established themselves on a broad basis in the field of medical laboratories. The fulfillment of the relevant standards for a medical laboratory is certified by a so-called quality certificate. As part of this certificate, the medical laboratory must undergo regular tests, which are referred to as "audits".

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