Medical Laboratory Technology (MLT)

Overview:-

• Medical laboratory technology is the branch of medical science responsible for performing laboratory investigations relating to the diagnosis, treatment, and prevention of disease.

• It has been said that 80% of medical diagnoses are made or confirmed by laboratory values.    

• Healthcare professionals do not know what the term medical technician means. 

History of  Medical Laboratory Technology:-

• In the early 19th century  French soldiers were attacked by yellow fever. A large number of French soldiers died as a result of infection by an organism for which the means of transmitting the disease were not understood. 

• Researchers discovered that transmission to humans occurred chiefly by the bite of an insect vector, a mosquito, and lead to the development of a vaccine in the early 20th century.

• In the 1930s a great deal of attention began to be focused on the clinical laboratory. not only for infectious but also for other metabolic tests for diagnosing diseases.

• At the beginning of clinical testing to diagnose disease states and to assess the effectiveness of treatment or recovery the physician performed his own tests in the patient's home.

How Medical Laboratory Technologists Work:-

MTs work in labs and usually must spend a lot of time on their feet. They're required to wear masks, gloves, goggles, and other protective equipment while they work. They must also use procedures that help mitigate their risk of coming into contact with infectious materials.

Those who work in a hospital or other facility that is open 24/7 may be required to work evenings, overnights, weekends, and holidays.

Types of Medical Laboratory Technologists:-

• MLTs who work in small laboratories may perform a variety of tests, but those employed in larger labs may be more likely to specialize in one area.

• Microbiology technologists work with bacteria and other microorganisms.

• Immunology technologists concentrate on the immune system and its response to foreign bodies.

• Blood bank technologists collect, examine, classify, and prepare blood for transfusions.

• Clinical chemistry technologists work with body fluids and analyze their chemical and hormonal contents.

• Cytotechnologists examine cells under a microscope for abnormalities that may lead to cancer.

Medical Laboratory Technologist vs. Medical Laboratory Technician:-

• A medical laboratory technologist and a medical laboratory technician work in related occupations and the terms may be confused, but there are a number of differences.

• Because technologists must earn a bachelor's degree, they have a much more extensive theoretical knowledge base than technicians, who need only an associate degree. 

• When it comes to job duties, technicians collect, process, and analyze specimens. They perform lab procedures and maintain instruments. 

• Medical laboratory technologists conduct the same procedures technicians do but also execute sophisticated analyses. They evaluate and interpret the results, conduct research, and develop new methods.

Other Duties and Responsibilities of Medical Laboratory Technicians Include:-

• Records of the test results in the lab's record book or daily file

• Collecting, preparing, and storing specimens

• Explaining lab testing procedures to patients and other clients

• Receiving, examining, and approving samples collected by physicians, nurses, and other medical professionals and ensuring that the right type, integrity, and quantity of samples are presented for the ordered tests.

• Preparing various lab reagents and standard volumetric solutions for use in a variety of tests

• Maintaining a clean and safe working environment

• Standardizing testing procedures to ensure consistent reliability and usefulness of test results
• Calibrating equipment, developing standard operating procedures, and determining correct reference ranges for various tests

• Using automated equipment and computerized lab instruments capable of performing several tests at the same time.

There are many Medical Lab Tests including:- 

• Blood Banking Tests —Typing, antibody screening, and cross-matching that are used to identify and prepare blood components that are compatible with transfusion.

• Chemistry Tests —Those tests for the measurement of electrolytes, glucose, lipids, proteins, hormones, enzymes, trace metals, drugs, and toxins.

• Cytogenetic Procedures —Techniques for chromosome counting and identification of abnormal chromosomes and disease genes.

• Cytology Procedures —Staining and examination of tissue samples in order to identify cancerous changes within cells.

• Hematology Tests —Tests to count and classify blood cells, and diagnose blood diseases including coagulation disorders.

• Histology Procedures —Cutting, staining, and mounting of specimens for microscopic examination by pathologists.

• Immunology Tests —Tests that are used to determine a person's ability to resist infections, diagnose autoimmune diseases, allergies, and infectious diseases, and determine tissue compatibility for organ transplantation.

• Medical Laboratory Technician —A clinical laboratory worker who may perform all levels of testing including quality control monitoring, specimen processing, and other laboratory operations.

• Medical Technologist —A clinical laboratory worker who performs all levels of testing, evaluates laboratory methods, verifies results, detects and resolves analytical problems, performs quality assurance, and consults with physicians and allied health professionals regarding laboratory services.

• Microbiology Tests —Those tests for the isolation and identification of pathogenic bacteria, yeast, fungi, parasites, and viruses and antibiotic sensitivity testing.

Where can we work when we finished our MLT Studies?

• We can work as “Medical Laboratory Technologists’’ in private sector hospitals letter on we can promote to “Lab charge, Lab Supervisor or Manager”.

• We can work as “Medical Technologists” in the government sector,  diploma holder    “Technicians” join the government sector.

• We can work as “Research Assistants” in research laboratories and research project letters and we can promote to “Scientific Officers”.

• We can work as “Quality Control Officers / Managers”  in clinical laboratories.

• We can join Public sector colleges and universities as “Lecturer or MLT”.

• We can join “Pharma Companies, Genetic Research Lab, Drug Testing Lab, Marketing Manager”.

What is the average salary of a Medical Laboratory Technology graduate:-

A Medical Laboratory Technology graduate can earn up to Rs 30,000 (LKR) per month. This can go up to Rs 50,000 (LKR) per month with an increase in the experience of the candidate.

MLTs who are employed in public healthcare facilities receive higher salaries compared to those who work in private hospitals, clinics, and diagnostic laboratories. 

MLTs who work in metropolitan areas also receive higher salaries than those who work in non-metropolitan areas.

The work environment of medical laboratory techs:-

Medical laboratory technicians work in a range of settings, including the following:

• Hospital laboratories
• Commercial laboratories
• Diagnostic laboratories
• Blood and organ banks
• Fertility centers
• Biotechnology companies
• Pharmaceutical companies
• Public health organizations
• Research facilities
• Reference laboratories
• Medical equipment sales companies

Skills to become a successful medical laboratory technician:-

In addition to the technical skills you will acquire in school and an aptitude for science, you will need the following soft skills to become a successful medical lab technician:-

• Reading comprehension: You must be good at understanding and following physicians' written instructions.

• Attention to detail: Precision is of the utmost importance when performing testing procedures.

• Critical thinking: This skill allows you to determine your options when solving problems or making decisions, compare them and then choose the one with the most positive outcome.

• Problem-solving: You must be good at identifying problems and solving them as soon as possible.

• Active listening: You must have excellent listening skills to effectively communicate with patients and fellow medical personnel.

• Dexterity: You must also be skilled with your hands because you work closely with needles and precise lab instruments. You must handle these tools effectively.

• Physical stamina: You must have physical stamina because you will work on your feet for long periods while gathering samples. You may need to turn or lift disabled patients to collect samples for testing.

How to become a Medical Laboratory Technician:-

Here are the typical steps to follow to become a medical laboratory technician:

1. Earn a high school diploma or equivalent.

2. Pursue post-secondary education.

3. Obtain state licensure.

4. Obtain certifications.

5. Pursue continuing education.

Branches of  Medical Laboratory Technology [ MLT ]

Which type of test is performed in MLT labs?

• Examining and analyzing body fluids and cells.
• Determine the chemical content of fluids.
• Look for parasites, bacteria, and other microorganisms.
• Match blood for transfusions.
• Test for drug levels in the blood.

Four types of laboratory biosafety level

Level 1 – least level was no threat during the deal with the sample.

Level 2 – moderately affect the worker but is curable in short-term treatment.

Level 3 – may cause serious or lethal disease via aerosol transmission simple inhalation of particles or droplets. Require long-term treatment.

Level 4 – extremely dangerous and pose a high risk of life-threatening disease. Treatment is not available.

Other names for Medical Laboratory Technology

• In India, it is called MLT also CLT [Medical/ Clinical Laboratory Technologist]
• But in foreign named as MLS/CLS [ Medical / Clinical Laboratory Scientist ]

 

Differences between Medical Laboratory Technology & Medical Laboratory Scientist?

• Technician- a person who has done diploma or certificate.
• Technologist -a person who have done bachelor's degree at least, and a technician works as a technologist. A technologist's position is above that of a technician.

Professional Role & Ethics of MLT?

• Follow all the safety precautions
• Test reports should be given to an authorized person
• Practice proper professional skills to avoid mistake
• Don’t disclose the personal information
• Keep in touch with the latest development in the field
• Dedicate towards profession to benefit mankind
• But it plays an important role in patient care by providing timely. Accurate reliable test results to health -care team members.

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CARDIAC CATH LAB EQUIPMENTS

X-Ray Generators:- 

The X-Ray generator produces X-Rays when an electrical current is applied to it. The X-Ray generator could be a device that acts because of the primary control mechanism for the whole fluoroscope. It’s through the X-Ray generator that current is allowed to flow into the thermionic vacuum tube. The fundamental function of adjusting the voltage differential and current of the tube is controlled automatically to keep up optimal contrast and brightness. 

Generator types utilized in fluoroscopy include single phase, three phases, constant potential, and high frequency. High-frequency generators provide superior exposure reproducibility, with the foremost compact size, lowest terms, and lowest repair costs. As a result, high-frequency generators are commonly utilized in new radiographic equipment. X-rays could also be generated in either an eternal or a pulsed mode. Automatic brightness control may be a standard feature of the bulk of contemporary fluoroscopes. Through this method, mA and kVp are constantly monitored and adjusted to optimize the image.  

X-Ray Tube Assembly:-

The majority of x-ray tubes found in current cardiac cath labs contain only two focal spots. The little spot will have a nominal size of 0.5 to 0.6 mm with a kW rating for one exposure of 40 to 50 kW. The big focal spot is going to be 0.9 to 1.2mm in size with a kW rating of 80 to 110 kW. The massive focal spot kW rating should be reasonably matched to the utmost kW of the generator. It’s used for cine or digital image recordings. 

The tiny focal spot is employed primarily for fluoroscopy. The tiny focal spot is additionally the proper choice for cine or digital image recordings of young children. The most common anode diameter provides a 100 mm diameter focal track. This diameter provides an affordable compromise between the specified tube loading and also the delay required to accelerate the anode rotational speed from low speed [approximately 4000 revolutions per minute (rpm)] used during fluoroscopy to high speed (10,000 rpm) used during cine acquisitions. The surface of the anode is usually a tungsten-rhenium alloy; the rhenium is added to smooth the surface of the anode and to cut back the loss of radiation output. 

The body of the anode is sometimes graphite, which increases the warmth energy that can be stored without damage thanks to increases in temperature. The specified small anode angle could be a compromise between field coverage and the warmth capacity rating of the tube. A minimum of a 9-degree angle is important to hide a 9-inch field of view (FoV) image intensifier at a Source Image Receptor Distance (SID) of 30 inches. 

The anode chilling rate should be a minimum of 400,000 heat units per minute (HU/min). Units with medium to large workloads should be equipped with circulating liquid (oil or water) heat exchangers to more efficiently and quickly convey heat from the anode body of the encircling atmosphere outside the tube. This exchanger typically quite doubles the warmth dissipation rate of a fan-cooled housing which is often 100,000 HU/min. This accelerated cooling allows the cardiologist to continue the case, mixing fluoroscopy with cine acquisitions without a forced delay. 

Tube Stand:-

The tube stand supports both the electron tube housing with the collimator and therefore the image intensifier with the imaging chain. It’s designed to keep up the alignment of the central ray for the x-ray beam to the middle of the image intensifier while the angle of the central ray changes within either the coronal or transverse plane of the patient’s body. This cranial-caudal or lateral rotation of the X-ray tube and image intensifier provides the required compound imaging angles required to minimize superposition within the image of the tortuous coronary arteries. 

The cardiologist places the anatomy of interest at the intersection of the 2 orthogonal rotations, the isocenter, to forestall the movement of the anatomy across the FoV of the image when the compound angles are adjusted. Translational movement of the image intensifier parallel to the central ray is accomplished by providing a variable focal spot-to-image receptor distance (SID) of a minimum of 90 to 120 centimeters (cm). 

This enables the positioning of the input plane of the image intensifier near the exit plane of the patient no matter the patient's thickness or compound angle to reduce magnification and geometric unsharpness within the image. The stand should provide extra movement (e.g. Rotation about its floor or ceiling support) to permit the equipment to be quickly removed from the vicinity of the patient when emergency access is required. Collision guards or slip clutches are provided to forestall further power-driven motion of the stand upon contact with the patient or other stationary objects.

Patient Table:-

Floor-mounted special procedure table tops in cath labs are typically supported by a pedestal base with motorized vertical motion sufficient to position any part of the patient’s body at the vertical isocenter of the imaging plane. The tabletop should be wide enough to support the patient, but narrow enough to permit the positioning of the image intensifier adjacent to the exit plane of the patient during lateral imaging. 

The length of the table must be sufficient to comfortably support a tall adult, with some additional room. The composition of the many tabletops is often carbon fiber material. This composition provides the strength required to support a minimum of a 350-pound patient cantilevered from the pedestal support while minimizing the attenuation of the diagnostic x-ray. The tabletop must “float” with regard to the pedestal when electromagnets are released to permit axial and transverse motion of the tabletop relative to the isocenter of the imaging equipment. The longitudinal and transverse motion of the tabletop respectively should be at least 100 cm and 30 cm

Control Console:-

The control console for a cine system should have the flexibility to pick both fluoroscopic and cine technique factors. For fluoroscopic operations, there should be selection switches to vary from continuous to pulsed fluoroscopy. Pulsed fluoroscopy should be available from 30 pulses per second to a minimum of 7. 5 pulses per second. For all modes, the utilized kVp and mA should be displayed on an easy-to-read display indicator. Moreover, the cumulative fluoroscopy time should be displayed and a “5-minute (of elapsed fluoroscopy time) buzzer” should clearly be heard in both the procedure room and also the control booth. It’s also helpful to own a fluoroscopic lock switch that may “hold” a specific combination of “kVp/mA.” 

The utilized FoV of the image intensifier should even be clearly displayed on the control console. Some units allow manual selection of kVp/mA during fluoroscopy additionally to the Automatic Brightness Control (ABC) of fluoroscopy. The cine controls typically have a gaggle of pre-established programs from which to pick appropriate technique factors. In general, cine frame rates from 15 to 60 fps should be available. Adult cardiac cine is typically performed at 30 fps and pediatric frame rates range from 30 to 60 fps cine pulse widths are typically 2 to 10 msec. The X-ray tube potentials should start above 60 kVp so as to limit the patient radiation dose and may go up to 120 kVp. Cine tube current values generally range from 50 to 800 mA. 

The ABC system automatically adjusts some combination of kVp, mA, and pulse width during cine operation to take care of the appropriate image quality. For cine, there should be several pre-programmed technique factors using different frame rates, starting kVps, starting pulse widths, and cine run durations. The control console should, at a minimum, display the cine kVp and mA(s) on an easy-to-read alphanumeric display. The sunshine levels exiting the image intensifier could also be indicated during cine filming as a relative check of proper cine film exposure. There should even be a button to mechanically advance the cine film (“jog” button). 

Finally, the control console should have an indicator to indicate the amount of film left within the cine film magazine. Digital imaging systems need similar function-related buttons. There should even be an “x-ray on” indicator and/or a door interlock indicator.

Grids:-

Cardiac imaging often employs lateral oblique projections that attenuate the x-ray beam and produce a big number of scattered photons. The scattered photons tend to scale back the contrast of coronary arteries and obscure the visualization of smaller arterial vessels and branches. Hence, the utilization of appropriate grid(s) to get rid of much of the scattered radiation leads to a contrast improvement and a capability to work out smaller vessel sizes. The usage of grids may lead to a rise in radiation dose to the patient by an element of two to 4 times. 

The best grid would offer a high percentage of primary radiation transmission and a high percentage of scatter radiation attenuation. The grid should be circular in shape so as to properly fit the image intensifier and to make sure the alignment to the central ray of the x-ray beam is necessary to forestall the grid cut-off of primary photons. Usually, carbon fiber interspace material is used so as to enhance primary radiation transmission. 

Although parallel and crossed grids are employed in the past for cardiac studies, the foremost common grid for these studies may be a focused grid. So as to accommodate a spread of SIDs, low grid ratios are utilized. Typically, grid ratios of 4:1 up to 8:1 are used. The focal length of the grid depends upon the x-ray tube/image intensifier mechanical web being used. 

Modern cardiac imaging systems typically have the capability to vary the SID from 80 cm up to 120 cm. The grids should have a usable focal range that accommodates these variations. It’s important to possess the grid lines mounted perpendicular to the TV raster lines to avoid interference patterns. Because the grids are stationary, thick grid lines would obscure small vessels. 

Therefore, thin grid lines with a high number of lines per inch are usually employed. Finally, there should be a mechanism to simply remove grids for physics/x-ray service test procedures. This feature also allows the removal of the grid by the operator when air gap techniques are wont to geometrically magnify the pediatric patient’s small anatomy within the image.

Television System:-

Digital recording of fluoro and cine images is usually taken from the television System. Hence, the television system should be designed to provide appropriate image quality for these studies. Foremost, the television system for cardiac studies should exhibit minimal persistence of the images so that frame rates up to 60 fps can be accommodated. This feature is termed minimal lag and must be measured with a dynamic test, such as the spinning spoke patterns.

Digital Imaging Systems:-

The challenge with digital imaging is the sheer volume of digital data. Typical diagnostic cardiac catheterization procedures in adults involve the imaging of 5 to 10 runs of a 6 to 7-second duration each with 30 fps. Thus, each patient study contains 2000 or more images. The minimum specifications of a 512 × 512 matrix and a pixel depth of 1 to 1.5 Bytes (8 to 12 bits) to capture the transmitted x-ray intensity data result in each image and also the entire study containing about 0.25 to 0.39 and 500 to 750 Megabytes (MB) of information, respectively. 

While the improved spatial resolution of 1024 × 1024 matrix is preferred, the larger matrix size has the disadvantages of increased quantum mottle and/or radiation dose to the patient still the maximum amount larger data rates and total image data. The info acquisition rates for a 512 × 512 matrix are typically 7.5 to 12 MB per second which is adequate for 60 to 90 MHz; for the 1024 ×1024 matrix, the information rates would be fourfold greater. Bi-Plane Cardiac Cath systems double the information acquisition rates that will be handled. 

For these reasons, most current equipment utilizes the 1024 × 1024 matrix only at lower frame rates of imaging; whereas, the 512 × 512 matrix is routinely used for many clinical studies. The spatial resolution of digital systems is set by the image acquisition equipment (e.g., video system), the matrix size, and therefore the image intensifier FoV. Generally, the calculated spatial resolution is capable of half the matrix size/FoV in millimeters. For a 512 × 512 matrix with a 150 mm FoV, the calculated spatial resolution would be about 1.7 LP/mm. The 1024 × 1024 matrix size would increase the spatial resolution to about 2.5 to 3.0 LP/mm. while these values for spatial resolution are but cine film imaging, digital systems have improved dynamic range, image processing capabilities, noise suppression, and networking and have image storage/display advantages. 

Hence, many cardiac cath labs are utilizing digital cine image acquisition. Most current digital cine imaging is completed by digitizing the video signal from a high-quality camera. The analog signal from a piece of television equipment goes to a data converter (ADC) and so it’s transmitted to the digital storage buffer for temporary storage. In the future, one can expect analog television cameras to get replaced by CCDs which will directly acquire the image as a digital image. Moreover, the image intensifier and TV camera are also replaced by a right away radiation detector/imaging system in a very few more years; such systems are currently under development and testing.

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CATH LAB

The Cardiac Catheterization Laboratory, also known as the “Cardiac Cath Lab,” is a special room where doctors can perform minimally invasive tests and procedures to diagnose and treat cardiovascular disease. 

Surgery performed in a cardiac catheterization laboratory almost always involves small flexible tubes called catheters, which can be used in place of surgery to access the heart and blood vessels. 

The catheter lab has special imaging equipment that is used to view the arteries and check the flow of blood in and out of the heart. This information helps the care team diagnose and treat blocked arteries and other problems.

 CATH LAB

Cardiac Catheterization is Used to:-

• Assess or confirm the presence of coronary artery disease, valvular heart disease, or aortic disease 
• Assess myocardial function 
• Determine if additional treatment is needed (for example, interventional surgery or coronary artery bypass graft, or CABG, surgery

During cardiac catheterization, an elongated tube called a catheter is inserted into a plastic introducer sheath (a short hollow tube inserted into a blood vessel in the leg or arm). With the help of a special X-ray machine, the catheter passes through the blood vessel to the coronary artery. 

A contrast agent is injected through a catheter as it passes through the heart chambers, valves, and main vessels. This part of the procedure is called coronary angiography. Coronary artery disease is narrowing or blockage of the coronary (heart) arteries. After interventional surgery, the coronary arteries are opened, increasing blood flow to the heart. 

The digital photo of the contrast material is used to identify the location of coronary artery stenosis or blockage. Additional imaging procedures called intravascular ultrasound (IVUS) and fractional flow reserve (FFR), can in some cases be performed in conjunction with cardiac catheterization to obtain detailed images of the vessel wall. Currently, these two imaging procedures are only available in specialty hospitals and research centers. 

Using IVUS, place a miniature sound probe (transducer) on the tip of the coronary catheter. The catheter passes through the coronary arteries and uses high-frequency sound waves to generate detailed images of the inner walls of the arteries. IVUS produces accurate images of the location and extent of the patches. 

Uses FFR to pass a special wire through the artery and administer a vasodilator. This test functionally performs a very high-quality stress test on a small section of arteries.

Cardiac Cath Lab Procedures.

1. Cardiac Implant Closure Device:- The percutaneous closure of the patent foramen ovale (the opening between the heart chambers) is done using a special closure device connected to the catheter.

Cardiac Implant Closure Device

2. Cardiac Stent:- A small wire mesh tube (stent) is inserted into the blocked artery to restore blood flow to the heart muscle.

Cardiac stent

3. Cardioversion:- A catheter is placed in the heart to locate and map small clusters of heart cells that cause the abnormal rhythm. Send a signal along the catheter to silence the cells, which results in an abnormal rhythm.

Cardioversion

4. Catheter Ablation:- A catheter placed in the heart locates and maps the small groups of heart cells that cause abnormal rhythms. The signal is sent along the duct, silencing the cells and causing the abnormal rhythm.

Catheter Ablation

5. Coronary Arteriogram:- A coronary arteriogram is an operation in which a very thin catheter or tube is passed from the groin, neck, or arm through the artery to the coronary arteries that surround the heart. The doctor uses the catheter to inject a contrast medium into the blood of the coronary arteries. The dye shows up on the x-ray and highlights the coronary arteries. X-rays are called angiography. It’s an X-ray examination of the coronary arteries. The catheter is placed in the coronary arteries to evaluate the arteries and pumping chambers of the heart.

Coronary Arteriogram

6. Electrophysiology Evaluation:- A study to understand the origin of heart rhythm disorders. The small catheter enters the heart through the femoral artery or brachial artery and is used to test the electrical system of the heart. It can induce the patient’s abnormal heartbeat for diagnosis and treatment.

Electrophysiology Evaluation

7. Electrophysiology Syncope Study:- A test to diagnose the cause of syncope. While monitoring the ECG and blood pressure, the patient’s bed is tilted from a flat position to an upright position. Once the individual’s response is recorded, treatment can begin to prevent a recurrence.

8. Internal Cardioverter Defibrillator Implant:-  A small device implanted in the chest that can be used as a pacemaker or to generate a slight electric shock when needed to restore a normal heart rhythm.

9. Angioplasty:-  The healthcare provider uses fluoroscopy during surgery. It is a special type of X-ray, just like X-ray “film.” When the contrast dye passes through the artery, it can help the doctor find the blockage in the heart artery. This is called coronary angiography. 

10. Rotoblation:- Rotablation (Rotational atherectomy) may be a complex and also the most challenging technique in coronary intervention utilized in patients with heavy calcification in coronary arteries (hardened arteries) to deliver stents in position to enhance blood flow. it's essentially a drilling technique with the assistance of a special diamond tip burr, which rotates at a speed of 150,000 to 200,000 rotations per minute. This drilling technique clears the within of the arteries to assist pass the balloon and stent easily. The tubes or catheters employed in this method are bigger than the conventional catheter.

Cardiac Catheterization Risks

Cardiac catheterization is usually safe. But as with any procedure that involves getting into your body, there are risks. Your doctor will discuss the risks with you and will carefully reduce your chances of developing these risks. Risks may include: 

• Blood vessel perforation 
• Air embolism (when air enters the blood vessel; this can be fatal) 
• Allergic reaction to the dye 
• Bleeding 
• Thrombus 
• Contusion 
• Seizure 
• Kidney infection from dye 
• Stroke 
• Uneven or irregular heart rhythm (arrhythmia)

👉Click Here to Read About Cardiac Cath Lab Equipments...

ABG Machine

 Introduction:

The amount of arterial gases, such as oxygen and carbon dioxide, is measured in an arterial blood gas (ABG) test.

In whole blood specimens, analyzers are utilized to assess blood gas, pH, electrolytes, and certain metabolites. They can measure pH, carbon dioxide, and oxygen partial pressures, as well as the concentrations of a variety of ions (such as sodium, potassium, chloride, bicarbonate) and metabolites (e.g.: calcium, magnesium, glucose, lactate).

ABG analysis is also used to detect acidosis and alkalosis conditions, kidney and lung function, response to treatment, and acid-base balance in the body.

Overview:

Some of the attributes of ABG machines covered in this article include: 

• what an ABG machine is
• what it is used for
• where it is utilized
• what the risks are
• advantages and disadvantages of ABG machine systems.

What is an ABG machine?

An ABG (Arterial-Blood Gas) machine, also known as Arterial-Blood Gas Analyzer, is used to measure the amount of oxygen and carbon dioxide (called blood gases) in the blood. It is also used to determine the blood pH (Power of Hydrogen). 

What is a Blood gas Test?

The amount of oxygen and carbon dioxide in the blood is measured by a blood gas test. It can also be used to determine the pH, or acidity, of the blood.  A blood gas analysis or arterial blood gas (ABG) test is the most popular name for the test. Throughout the body, red blood cells deliver oxygen and carbon dioxide. They are known as 'Blood gases'. When blood travels through the lungs, oxygen enters the bloodstream, while carbon dioxide exits the bloodstream and enters the lungs. The blood gas test can show how successfully the lungs exchange oxygen into the bloodstream and eliminate carbon dioxide from the blood.

Why is the ABG machine used?

• The ABG machine is used to diagnose several breathing and lung conditions such as chronic obstructive pulmonary disease (COPD), or cystic fibrosis (a life-threatening hereditary disorder that affects the lungs and digestive system).

• To check if the blood requires extra oxygen or any assistance with breathing.

• To check the acid-base balance present in the blood. There can be too much acid in case of kidney failure, infection, or any toxic component intake.

• To monitor whether and how the lungs are responding to treatment.

• To monitor if the lungs are removing the right amount of carbon dioxide (CO2).

• To monitor vital kidney functions.

• To find the presence of respiratory acidosis, respiratory alkalosis, metabolic acidosis, or metabolic alkalosis.

How does the ABG machine work? 

• At 37°C, blood gas analyzers have three electrodes that measure pH, PCO2, and PO2. They were first introduced in the 1960s, after innovations by R Stow (CO2) and L Clark (PO2) in 1954.

• Electrodes are used in blood gas/pH analyzers to determine pH, carbon dioxide partial pressure, and oxygen partial pressure in the blood. 

• A dry reagent pad system is used in chemistry analyzers, in which a filter pad impregnated with all of the chemicals required for a certain reaction is placed on a thin plastic strip. 

• The ion-selective electrode (ISE) approach is used in electrolyte analyzers, in which measurements of ion activity in a solution are made potentiometrically using an external reference electrode and an ISE with an internal reference electrode.

How is blood prepared for an ABG test?

The only anticoagulant used to prepare blood samples for blood-gas analysis is Heparin. Inadequate anticoagulation and the production of tiny blood clots, which can block the sample stream of blood gas analyzers and invalidate results, are two of the most common practical difficulties associated with blood gas analysis.

How is an ABG machine operated?

Whole blood samples are put into the analyzer in tubes, reaction cuvettes (a piece of laboratory equipment designed to contain samples for spectroscopic analysis), syringes, capillaries, or test strips. It is critical to remember that no blood should be injected or poured into the machine. Using a keypad or a linked computer, the operator can pick the tests that will be performed on the sample.

Where is the ABG machine used?

Hospital, patient bedside, physician's office, clinical laboratory, and home are some of the places where this device is used.

How is the blood drawn for the ABG test? 

Blood is usually drawn from an artery. Blood from a vein may be used in some instances (venous blood gas).

Blood is most typically drawn from one of the following arteries:

• The radial artery (wrist)

• The brachial artery (arm)

• The femoral artery (groin) 

Before collecting a blood sample from the wrist area, the health care professional may do a circulation test, also known as Allen Test (a test that determines whether or not the blood flow to the hand is normal. For a few seconds, the health professional drawing blood will apply pressure on the arteries present in the wrist. The blood flow to the hand will be cut off temporarily, and the hand will turn cool and pale).

A tiny needle is inserted through the skin into the artery by the provider. The sample is sent to a laboratory for analysis right away.

What are the main components of an ABG?

There are six main components to an ABG. They are as follows:

1. pH

2. Oxygen partial pressure (PaO2)

3. Carbon dioxide partial pressure (PaCO2)

4. Bicarbonate (HCO3)

5. Oxygen saturation (O2 Sat)

6. Oxygen concentration (O2 CT)

What are some of the body conditions that require ABG analysis?

The ABG machine is used to diagnose several breathing and lung conditions. Some of the common conditions ABG is used for are:

1. Respiratory acidosis:

Inadequate alveolar ventilation causes respiratory acidemia (acidosis), which results in the retention of carbon dioxide and an increase in free hydrogen ions. It happens when reduced breathing (hypoventilation) raises the concentration of carbon dioxide in the blood and lowers the pH of the blood.

2. Respiratory alkalosis:

Respiratory alkalosis is caused mainly by excessive carbon dioxide excretion/exhalation (hyperventilation), which results in the exhalation of more CO2 than is normal. As a result, the number of free hydrogen ions decreases, resulting in an alkaline condition.

3. Metabolic acidosis:

Excess fixed acid production, such as lactate or HCO3 loss, is a symptom of metabolic acidosis. It occurs when the body produces too much acid or when the kidneys do not remove enough acid from the body. Acidemia (acidosis) is characterized by a low blood pH (7.35) caused by the body's excessive production of hydrogen ions or its inability to produce bicarbonate (HCO3) in the kidneys.

4. Metabolic alkalosis:

Metabolic alkalosis is caused by a decrease in hydrogen ion concentration, which leads to an increase in bicarbonate, or is caused by increased bicarbonate concentrations.

How are the ABG results interpreted?

The pH should be checked first to see if the patient is within normal range, above the normal range, or below the normal range. A patient is in alkalosis if his or her pH is more than 7.45. If the pH is below 7.35, the patient is in acidemia (acidosis). Remember that the lower the pH number, the more acidic the body is. Even though the pH is normal, acidosis or alkalosis may still exist since the body can compensate to keep the pH balanced.

After that, examine the PaCO2 level. This will reveal if the variations in blood gas are caused by the respiratory system or by metabolic alterations. The medical expert will be able to fully interpret the blood gas when combined with the HCO3.

Below is a table to help in better understanding of ABG results interpretation:

ABG	pH	PaCO2	HCO3
Respiratory Acidosis	Low	High	Normal
Respiratory Alkalosis	High	Low	Normal
Metabolic Acidosis	Low	Normal	Low
Metabolic Alkalosis	High	Normal	High

· What are the normal ABG values?

pH	7.35-7.45
pCO2	35 mmHg – 45 mmHg
pO2	75 mmHg – 100 mmHg
HCO3-	22 mEq/L – 26 mEq/L
O2 Saturation	> 95 %

                             *mEq/L – milliequivalents per litre             *mmHg – millimetre of mercury

The normal value varies depending on the laboratory, machine model, and age factor (for example, infants may show different normal values compared to the elderly).

What are the risks associated with ABG?

A blood sample collected from an artery has a low risk of causing complications. Although sometimes, any test that requires the use of a needle entails the risk of bleeding, infection, and bruise. There may be some tenderness/soreness where the needle was inserted.

• There could be a tiny bruise on the affected area. It is advised to apply pressure on the location for at least 10 minutes after the needle is removed to reduce the risk of bruising.

• A nerve or an artery may be damaged by the needle in rare situations. The artery may become blocked as a result of this. 

• When the process is performed appropriately, there is very little risk. The size of veins and arteries differs from person to person and from one side of the body to the other. It may differ because drawing blood from some patients can be more difficult than from others.

Other concerns of having blood drawn are minor, although they can include:

• Feeling faint or lightheaded
• Several punctures are used to locate blood vessels.
• Hematoma - a type of hemorrhage (blood build-up under the skin)
• Excessive loss of blood
• Infection

What is the cost of an ABG machine?

In India, the price of an ABG Machine typically ranges from INR 3 lakh to INR 7 lakh.

What are the advantages of an ABG machine?

These ABG systems provide a number of advantages, including 

• Less maintenance, 
• Improved fault detection, and 
• Reliable quality control. 

Another benefit is a reduction in phlebotomy-related blood loss, which is critical in settings such as the operating room (OR) or intensive care unit (ICU), where blood conservation is critical. Analyzers are becoming faster, smaller, and more user-friendly, and they are demonstrating the potential to perform accurate testing with smaller blood samples.

What are the disadvantages of an ABG machine?

• One of the disadvantages includes a sample being mishandled or testing performed wrong. 
• In a hospital, emergency department, or big clinical laboratory, qualified healthcare providers perform blood gas analysis. 

These tests are "stat" tests, which means they should be completed as soon as possible after the sample has been collected. The obtained blood sample for arterial blood gases (ABGs) degrades rather quickly. Therefore, if a testing delay is anticipated, the sample should be maintained on ice and rewarmed later for accurate analysis. If any air bubbles remain in the top of the syringe after the sample has been collected, they must be removed. The syringe is then placed on ice and transferred for quick analysis when the needle is sealed.

Some instances of the sample being mishandled are:

If the sample contains air bubbles.

If the sample gets contaminated with venous blood.

If the blood sample coagulates due to insufficient heparin coating of the tube.

If there is an excess of heparin (liquid heparin will dilute the blood and cause changes in the pH value, leading to wrong value display).

Occurrence of hemolysis before the sample being placed in the ABG analyzer.

Another disadvantage could be a lack of proper documentation, leading to the loss of important patient details.

What are the instrumental errors that can occur in an ABG machine?

• The inaccurate temperature of electrolytes.
• Improper calibration of ABG analyzer
• Inadequate quality control and electrode maintenance (electrodes have various measurable lifespans).
• Poorly compensated non-linearity of the Clark electrode.

*(CLARK ELECTRODE - a well-known sensor for measuring dissolved oxygen concentration in a water solution. This type of electrochemical sensor has the advantage of being easy to detect extremely low oxygen levels. This electrode needs to be replaced once every 3 years as its Teflon membrane becomes coated with proteinaceous filth).

How to troubleshoot instrumental errors?

Ensuring proper maintenance of the machine:-

Frequent and adequate calibration of ABG analyzer. Calibration is a procedure performed on blood gas electrodes prior to testing blood samples to ensure that readings are accurate within the expected range.

Gases used for calibration should be exceedingly precise and able to be traced back to certification from the National Institute of Standards and Technology (NIST):-

Initial adequate Quality control checking of the machine and its parts.

When it comes to blood gas electrodes, quality control is monitoring the instrument's performance on a regular basis to ensure calibration, stability, and reliability.

The accuracy and precision of blood gas measurements are assessed using statistical approaches. 

The most controllable part of quality assurance is certainly quality control.

• The lifespan of the machine should be considered and appropriate measures should be taken. 

• Internal quality control processes are meant to ensure that a laboratory's instruments 

      (e.g., in this case, electrodes) function as expected. 

They consist of standard methods and protocols for detecting irregularities in performance. 

Most external regulatory or accreditation agencies (e.g., Joint Commission for the Accreditation of Healthcare Organizations [JCAHO], Clinical Laboratories Improvement Amendments [CLIA]) demand internal quality monitoring.

• No particular instructions for routine calibration can be supplied due to the many varying processes, designs, and recommendations of various manufacturers. Therefore, operators must follow the manufacturer's guidelines to the letter.

Article Contributed By:-

• Jenesha Blessey Jacob N - http://www.linkedin.com/in/jenesha-b-321391187