Semi-auto Biochemistry Analyzer: Features, Application, Maintenance

A semi-auto biochemistry analyzer is a machine that is necessary for doing blood tests such as glucose, urea, albumin, etc. It depends on the principle of filter photometry. The Filter photometry is slightly different from spectrophotometry.

You may find pre-set 50 parameters (approximately) in the machine. You can edit those programmings as you like. Also, you can add about 100 new programs in the empty slots. The semi-auto biochemistry analyzer can store around 400 patient results.

Components of Semi-auto Biochemistry Analyzer

1. Color Filter

Different colored filters are present in the machine which signify different wavelengths. They can be 6 -7 in number. Also, you may have an extra slot (1-2) for adding extra filters if needed. The common wavelengths of filters include 340 nm, 405 nm, 500 nm, 546 nm, 578 nm, 620 nm, and 670 nm. Just see your literature on the reagent kit for setting this wavelength. If you do not have the given wavelength in the machine, choose the wavelength closest to the required one.

2. Light Source

The most common light source is the halogen (6V/10W) light, which has got a life span of about 3000 hours (theoretically).  In some models, the light source can also be a LED light.

3. Photo-detector

Photo-detector measures the absorbance (optical density) of the sample solution.

3. Flow Cell/Cuvette

It is for the storage of the sample, once it is fed into a semi-auto biochemistry analyzer. You will find 32 μl of quartz flowcell inside your machine. If your flowcell gets damaged, then you can use a cuvette to get the reading. In this case, the biochemistry analyzer acts like a colorimeter. But, as long as possible, use a flowcell for taking the measurements.

4. Temperature Controller

The most common temperature controller found in a semi-auto biochemistry analyzer is the Peltier module. Also, in the machine, you can have the settings of temperature at 25°C, 30 °C, and 37 °C. If you need the room temperature, you can switch off the temperature setting.

5. Pumping System

A pump draws the sample from the sipping tube to the flowcell. Once the measurement is completed, it again draws the fluid out of the flowcell. The most common type of pump is the peristaltic pump. However,  you may even find a syringe pump for this purpose.

6. Incubator

You may find an inbuilt incubator for holding a few test tubes.

7. Thermal Printer

There is an inbuilt thermal printer at the top of the machine. In the setting menu, you can switch it to the OFF mode, if you do not need it. Else set it to ON mode. Once the printer paper finishes, replace it with a new one.

8. Fan

You can find a few brushless DC motor. They are necessary to maintain the set temperature and to cool the machine.

9. Display

It is generally  LCD type with or without a touch screen.

You can even use a membrane keyboard. Generally, a semi-auto biochemistry analyzer supports an external printer, mouse, and keyboard.

Semi-auto Biochemistry Analyzer Principle

Semi-auto Biochemistry Analyzer Principle
Semi-auto Biochemistry Analyzer Principle

A semi-auto biochemistry analyzer works on the principle of filter photometry. The halogen lamp radiates light in all directions. The radiated light then goes through a convex lens which converses the scattered light. After that, it passes through the sample present in the flowcell/cuvette. A part of light energy is absorbed by the sample. While the remaining light transmits. This transmitted light then goes through a color filter. The color filter passes the monochromatic light to the photo-detector. Then, the photo-detector transfers the light signal to an electrical signal which becomes an input for the microprocessor.

The machine measures the absorbance of the light by the sample. Then it follows the calculation of the given parameter on the basis of the end-point, kinetic, or fixed time kinetics method.

Operation of a Biochemistry Analyzer

First of all, sip the distilled water once you have turned on the machine. When your machine is ready to run, add or edit all the programming of every parameter that you need. Set machine to the flowcell mode. Set either an internal or an external printer mode. Then set the date and time, and the name of the hospital or the lab, that you are working on. You may not need to alter the pump speed.

For every kind of method you follow, you need to feed distilled water initially. Then for reagent blank, you also need to feed the reagent solution. And for the sample blank setting, you need to feed the sample blank solution.

For the two-point and end-point methods do the calibration with the help of a standard solution. Then save the factor that you get doing the calibration. Finally, cross-check it by feeding the standard solution as a sample solution.

Now feed the sample solution and get the result. Also, observe the graph on the LCD.

Parameters Measured by a Biochemistry Analyzer

Parameters Measured By Semi-auto Biochemistry Analyzer
Parameters Measured By Semi-auto Biochemistry Analyzer

Handling of Semi-auto Biochemistry Analyzer

  • If the space of the semi-auto biochemistry analyzer is about to be full, clear the data. Else, the machine may become slow to operate.
  • Always look for the condition of the tubing system. If there is leakage, replace it with the new one.
  • Never feed whole blood in the machine. Else, there will be clot formation in the tubes. This will block the path of the tubes and flowcell.
  • Make sure that the distilled water that you feed as a blank solution is not contaminated. Else, it will give you a fault reading.

1. Calibration

You need to do the calibration of the reagents in the following cases.

  • When you replace a reagent kit with a new one
  • When you replace a flowcell or light source

I suggest you, do calibration of every possible reagent at least once a week. But remember that, the more calibration you do, the better will be your result.

The system itself will have the features for different kinds of calibration such as pump calibration, sipping calibration, light intensity calibration, filter calibration, etc.

2. Absorbance (Optical Density)

Factors affecting the value of absorbance of the solution are as follows

  • Improper orientation of the flowcell in the machine.
  • If the machine is unable to sip in the solution, it will measure the absorbance of the air.
  • Replacement of the new light source or the natural aging of the existing light source will have variation in the intensity of the light. This will affect the absorbance of the solution.
  • If the light source is not working, then check the input voltage of the halogen lamp. If there is a proper supply voltage, then that means you need to replace the halogen lamp. On the other hand, if there is no voltage supply to the lamp, the problem may be on the mainboard.
  • The age of the photo-detector is inversely related to the value of absorbance. So, it is better to replace it after 3 yrs of use to get a better result.

3. Cleaning




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