Blood Gas Analyzers

Blood gas analyzers are the technologies that are used to measure the pH combinations, blood gas that is pCO2 and pO2, electrolytes. This technique also measures the metabolites parameters from whole blood samples. Blood conservation is very essential in every clinical diagnostic lab or critical care facility. It has a highly accurate blood gas analyzer that can streamline work processes and reduce errors with minimum maintenance. A unique feature in certain blood gas analyzers tools is liquid calibration. They eliminate the previously required gas tanks, regulators, tubing lines, and humidifiers.

Although blood gas analyzers have been used for clinical purposes for more than forty years. A new generation of portable and maintenance-free products continues to grow in popularity.

A blood gas analyzer is a powerful diagnostic tool in critical care. It can be an important diagnostic method in pre-hospital and in-hospital emergency therapy. This tool currently available offers a wide range of functions. These parameters are used by physicians in emergency cases to detect a broad range of life-threatening respiratory disturbances and acid-base imbalances. The early and exact diagnosis of these conditions in the field, as well as in the emergency department, allows for efficient, properly directed therapy.

Instrumentation of Blood Gas Analyzer

Blood gas analyzer works with three-in-built electrodes.

Blood gas analyzers consist of:
• pH-sensitive glass electrodes
• It has the partial pressure of CO2 in the blood
• It has the partial pressure of O2 in the blood

These chemistry analyzers in which a filter is impregnated with all reagents required for a particular reaction are placed on a thin plastic strip and also use a dry reagent.

Product Description Handheld device or benchtop device which is placed on a cart. It consists of a display usually LCD, a keypad to enter information, and a slot to insert a test strip or sample tube. Some systems may have alarms, memory functions, touch pens, USB ports to transfer the data to a computer, and also contain a small storage compartment for reagents.

Electrolyte analyzers use ion-selective electrode (ISE) methodology in which The measurements of the ion activity in the solution are made potentiometrically using an external reference electrode by the electrolyte analyzers ion-selective electrodes [ISE]. It is an ion-selective electrode containing an internal reference electrode.


• It does not have special settings requirements in battery-operated handheld devices.
• Approximately the dimensions [mm] are 100 x 300 x 400
• Approximately the weight (kg) is 1-5 for handheld units and 15-25 for benchtop units Consumables.
• Typical product lifetime (years): 4-6
• Shelf life (consumables): Reagents: 1-2 years

Types and Variations

• Handheld
• Portable
• Benchtop

Operating Steps

The entire blood samples are put in the tubes, on reaction cuvettes, or test strips. Then, the sample is loaded into the analyzer. The operator may decide the tests being performed on the sample using a keypad that is connected to the computer. Reported problems Operators should be aware of the risk of exposure to potentially infectious bloodborne pathogens during testing procedures and should use universal precautions, including wearing gloves, face shields, or masks.

Important components of Blood Gas Analyzer

Test Solution

• The blood is separated by the membrane which is permeable to carbon dioxide gases, but not permeable to the dissolved ions.
• Carbon dioxide gas which is present in the blood reacts with the buffer system to change the pH.
• The pCO2 electrode takes advantage of linear correlation between pH and log pCO2 over the range of 11-90mm Hg.
• The concentration of the hydrogen ions is also changed because the dissolution of the carbon dioxide is detected by the pH-sensitive glass electrode.
• A potential difference is present between the glass electrode and the reference electrode.
• This can be measured in the meter.

Reference Solution

• Platinum and electrode are immersed in a buffer solution.
• These electrodes are separated from the test solutions.
• Oxygen which is present in the blood diffuses through the membrane and is react with the buffer solution.

The following reaction takes place:

At platinum electrode that is cathode electro reaction occurs:


The electrons is essential for electro reduction are produced at reference electrode that is anode are as follows:

4Ag+ +4Cl-= 4AgCl+4e-

A potential difference is present and is measured in meters. The current is flowing in the system is directly proportional to pO2. It can be recorded directly after the amplification into PO2.

Advantages of Blood Gas Analyzer

The advantages of blood gas analyzer are as follows:

• These systems require less maintenance.
• This system has better error detection and consistent quality control.
• These traditional analyzers are still in use today.
• It requires more manual care of electrodes, quality control solutions, and waste management.
• Most blood gas analyzers offer automatic sample mixing.
• It is easy to use.
• It is also available in a lightweight.
• It has a small-footprint design.
• These models allow the simple replacement of solutions for analysis such as sensor cassettes and solution packs.
• It is also used in the hospital, patient bedside, physician office, clinical laboratory, home, etc.


There are the various application of blood gas analyzers:

• They are used to measure blood gas, pH, electrolytes, and some metabolites in the whole blood sample.
• They are also used to determine abnormal metabolite.
• They are used to measure the electrolyte levels in the blood and the patient’s acid-base balance and levels of oxygen/carbon dioxide exchange.
• They can measure pH, partial pressure of carbon dioxide and oxygen, and concentrations of many ions such as sodium, potassium, chloride, bicarbonate, and metabolites such as calcium, magnesium, glucose, lactate.

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