Analyzer are they wrong?
The answer to this question is yes, but it should be noted that in fact most of these errors are the fault of the device operator, not the device itself.
The main cases that can lead to an incorrect answer from the autoanalyzer include the following categories
Lack of initial calibration of the device
The first issue that must be addressed after starting the device is the calibration of the device. Of course, this should be done from time to time according to the recommendations of the device calibration tables using
Calibration control serum for biochemistry autoanalyzer and body electrolyte autoanalyzer,
2. With cell suspension (artificial or real) for hematology autoanalyzers (cell counters),
3. Calibration solutions should be done for the Blood Gas Analyzer
. In fact, the calibration of the devices is like the first brick, which, if tilted, will tilt the wall up to Soraya. The laboratory manager should leave this important task to his or her experienced staff.
In this regard, important points are reminded as follows:
● How to prepare the calibration serum:
A) Calibration serums are in the form of lyophilized powder and to dissolve it, you should use deionized distilled water and if it is not available, double distilled water.
B) Use the best and most accurate pipettes.
C) When removing the vial lid, some lyophilized powder always sticks to the vial lid. Carefully and gently open and close it, so that nothing is lost from the powder and all of it dissolves.
D) After closing the lid of the vial, you should put it in a special position (motionless or rotating or in the dark) for a certain period of time mentioned in the relevant brochure, so that it is ready for consumption.
● Calibrators of hematology analyzers:
This calibrator is in suspension. These suspensions are obtained by fixing normal cells with a fixator to maintain the life and consequently the number and volume of cells, but their shelf life is short.
The most important point in using these suspensions is that they must be completely homogeneous and homogeneous before use.
-made calibrator solution: These solutions are used in blood gas analyzers and are available in prepared form.
For all calibrators, remember that
: The important thing about any material, especially the calibrator solution, is the date of use.
2. If possible, prepare the solution or calibration suspension as needed so that there is no need to store the remaining solution.
3. If the suspension or solution is to be left in place for a while to be ready for use, make sure the vial lid is tightly closed and the ambient temperature is appropriate. Evaporation will cause the solution to thicken or suspend.
2. Problems in the sample (Sample) and sampling system:
Always deliver enough samples to the machine. If the sample is small and the device requires, for example, 100 microliters of the sample for glucose testing, but there is only 50 microliters of the sample inside the sample cup, assuming that the patient is a normal person with normal blood sugar, receiving an abnormal response. (Eg glucose 53mg / dl) We will notice a device error, but if this happens to a diabetic patient with high blood sugar, the device will mistakenly deliver a normal response. Remember that a normal answer is not always the right answer.
Another problem is the presence of small clots or narrow fibrin filaments. If there is a small clot in the narrow passage of the sampling tube of the device, the volume of the sample taken is certainly less than the limit defined for the device. In addition, the presence of this clot causes incorrect answers in subsequent samples. It is very important to note that when a serum sample is needed, you should not centrifuge a blood sample that has not yet coagulated and remove the serum for an emergency response, as this fluid is not yet in the serum and is It is clotting and will cause problems in removing the clot or fibrin filament from the device.
In the case of devices working with plasma or whole blood, sufficient anticoagulants should be present in the test tube, and the sample should be thoroughly mixed with anticoagulants after sampling. Otherwise, a small clot or fibrin fibers are formed, which in addition to the above problems, interferes with cell count, especially platelets and red blood cells, and cellular indices.
3. Problems with reagent or reagent harvesting system:
In new devices, a system has been installed that detects the presence of air bubbles in the reagent transmission system and considers it as a reason for the lack of liquid (reagent) and sounds the alarm. Therefore, the user will easily notice the end of the introduction. In older models that do not have this system, the device does not notice the end of the introduction and continues to work.
If you go to the previous steps from where you have the answer “zero”, you will see that in the previous few tests, since the solution was running out, there was not enough reagent and as a result the answer was incorrect (less or more than the actual value). ) Is obtained; So in such cases you have to repeat the last few tests, even if the answer is normal.
Another problem that may occur is that the user may mistakenly place one identifier in the position of another identifier, in which case the device will not notice this error. To fix this error, the devices have recently been equipped with a barcode recognition system so that it can find the desired solution without a line.
4. Problems at the reaction site inside the device:
The reaction site in the autoanalyzer may be fixed (in most autoanalyzers , such as a hematology autoanalyzer) or interchangeable, such as a tray coat (in most biochemical autoanalyzers).
The location of the reaction can be considered in two ways:
1.Reaction site temperature: Most biochemical tests are performed at 37 ° C and this temperature can be controlled by sensors with high accuracy. In the case of devices with a 37 Mar (hot water bath) at 37 ° C, it is important to note that the tank must be deionized with distilled water and, if not available, double-distilled with distilled water. The use of ordinary water causes sediment to gradually settle on the temperature sensors and reduce its sensitivity.
2. Cleanliness of the reaction site: This is also controlled by sensors, but these sensors do not understand certain conditions that can lead to incorrect answers. For example, if you want to use a replaceable and washable tray for the TIBC Fe Ca and Mg tests, it must be washed with acid (Washed) and it is not enough just to be clean. This is the responsibility of the machine operator, not the machine.
5. User does not pay attention to the warning signs of the device (Flag):
Fortunately, there are intelligent warning systems in all auto-analyzers that alert the user to a malfunction in the form of a flag. These symptoms are of two types:
1.Symbols determined by the user’s prior planning; Like the normal range of a test that is reported by the device if there is an answer outside the range of the H or L sign and indicates the need to re-examine the same test on the sample.
2. Symbols that are specific to the device and are defined by the manufacturer in the processor; For example, if the number of cell counts in a hematology counter is three times greater than each other, the device will indicate it with a ٭ or other sign, which may be due to noise in the device or other causes.
In any case, the laboratory manager should prepare a list of warning signs for each device and expose them to the users’ attention and attention so that in case of personnel change, even the newly arrived personnel know what action they should take in case of any of these warning signs. . Apart from the above, one of the most important factors that can reduce the occurrence of errors in the machine is the regular and regular washing of the devices according to a specific schedule with the washing solution. Generally, autoanalyzers have their own washing solution. Some wash the machine at the end of each test cycle and prepare it for the next test, and some also wash the machine at the end of the working day (with the Shut down command or similar command).
Rose Calibration Company in Melbourne, Australia with over ten years of experience provides all calibration, maintenance, and repair services throughout Australia. If you live in Sydney, Melbourne, Adelaide, Perth, Geelong, and Brisbane, you can receive your quote in less than two hours by fill-up the form via the “Booking” link.