How are blood tests conducted?

The lifeblood of medicine is medical laboratory testing. It offers vital information that dates back thousands of years and helps doctors identify and cure illnesses. Unfortunately, neither the general public nor the medical community have a good understanding of the area of laboratory medicine.

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One of the two primary subfields of pathology, which is the study of the causes and consequences of disease, is laboratory medicine, sometimes referred to as clinical pathology. Many laboratory disciplines are covered by pathology, including microbiology and blood banking. Clinical pathology uses laboratory study of bodily fluids, including blood, urine, feces, and saliva, to identify diseases. Anatomic pathology, the other discipline of pathology, uses bodily tissue examination to provide a diagnosis.

We are scientists working in medical laboratories and public health with a focus on infectious illnesses and microbiology. From the time your doctor requests a blood test until a diagnosis is made, there are several stages involved. This is the procedure for laboratory testing from the bedside to the lab bench.

Everything begins with a sample.

Sometimes a doctor’s physical examination and thorough medical history are sufficient to diagnose a problem, provide advice, or write a prescription for medicine. Nonetheless, there are certain situations in which your doctor might want more details in order to provide a precise diagnosis. Many times, testing like blood work or imaging scans provide this information.

The first step is to have your blood extracted via a procedure called phlebotomy. To take a blood sample, a medical professional—usually a nurse or phlebotomist—sticks a needle into a vein.

It might be necessary to use multiple blood tubes since some tests can only be done with specific kinds of blood specimens. For instance, blood must be drawn with a chemical that stops the blood from clotting for one test that is frequently used to identify anemia. Contrarily, blood is frequently drawn from patients who are being assessed for a clotting issue in a tube that also contains an additional anticoagulant.

Examining routes

After that, specimens are transported to a clinical laboratory. Laboratories can be found in public health settings like the Centers for Disease Control and Prevention or a state public health laboratory, or they can be found within hospitals, reference labs, or doctor’s offices. More than 320,000 federally licensed laboratories employing more than 329,000 laboratory specialists in the United States as of 2021. In addition to the more than 1 billion COVID-19 tests ordered during the epidemic, an estimated 14 billion laboratory tests are ordered annually in the United States. A laboratory has several automated sections since there are so many specimens to evaluate and examine.

The biological, chemical, and physical characteristics of the molecules and cells that comprise a blood samples are examined in laboratory testing. Often, centrifuging a blood sample into distinct components is the initial step. This separates the sample into two sections: one containing liquid components and dissolved solutes (serum or plasma) and the other containing solid components (such as cells).

A blood specimen’s serum or plasma can be analyzed to determine the body’s concentration of various chemicals. Among the most typical ones is your blood glucose concentration, or blood sugar level. Knowing how high a patient’s blood glucose is can help doctors diagnose their patient more accurately or make sure the illness is under control for the more than 37 million Americans who have diabetes.

Your doctor will take samples to check for the presence of a pathogen if they think you have an illness. For instance, they could take a urine sample to check for urinary tract infections or a throat swab to check for strep throat. These samples are incubated by scientists to weed out any organisms that proliferate and resemble potential diseases. They could carry out more tests to determine the microbe’s identity. The medical laboratory specialist can identify an organism, test a range of antimicrobial medicines against it, and then advise your doctor on the best course of action for treating your illness.

Medical laboratory testing’s evolution

In the United States, the first hospital clinical laboratory opened its doors in 1894. Professionals in laboratories have been analyzing materials using some of the same techniques for more than a century.

In 1882, the Gram stain became one of these standard tools. It distinguishes between two distinct kinds of bacteria by using two different dyes and taking advantage of variations in the bacterial cell wall. This aids in the selection of the most effective antibiotic treatment for an illness by lab scientists.

The Coulter Principle, another widely utilized method, was created in the 1940s to classify and identify individual cells according to their physical dimensions and electrical current resistance. Complete blood counts, which assess abnormal increases or decreases in the number of different types of blood cells and may shed light on certain diseases or conditions like cancer or sickle cell anemia, are frequently performed by medical laboratory specialists using this approach.

The Nobel Prize-winning polymerase chain reaction technique was developed in 1986 by scientists to quickly create numerous copies of a pathogen’s DNA in a sample. PCR is often used to detect genetic diseases, diagnose infections, and track the development of cancer.

PCR was followed by an explosion of contemporary laboratory instruments for disease research and diagnosis. A couple of these state-of-the-art instruments are matrix-assisted laser desorption ionization (MALDI), which is one of the most widely used methods for identifying bacteria that are hard or impossible to cultivate. Scientists may modify an organism’s DNA using genome editing and CRISPR-Cas9, which helps identify diseases and identify genes that are malfunctioning by adding, deleting, or changing desired genes. In order to ascertain the genetic material’s sequence in biological samples, next-generation sequencing has emerged as a potent contemporary instrument. It has been widely employed in pathogen monitoring and variant identification, including the virus that causes COVID-19, in wastewater.

Problems and solutions

Because mistakes might happen throughout the testing procedure, comprehending and interpreting test findings is one of the most important issues in laboratory medicine. For reliable findings, specimens need to be gathered and transported to the lab correctly. Similarly, at-home exams must be kept in a safe location. Together with the patient’s unique situation, clinicians and patients must evaluate the possibility of false positive or negative results by taking into consideration the test’s limitations.

Working together, medical laboratory specialists and doctors may be able to lower the number of diagnosis and treatment mistakes. Laboratory data can be very helpful in patient care, but appropriate diagnosis and treatment need a comprehensive strategy that considers a patient’s medical history, genetics, and lifestyle choices, among other things. Even though a lab result is strong, it shouldn’t be applied alone. For patient treatment to be effective, laboratory test results must be communicated clearly and accurately.


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