Advantages And Limits Of Clinical Analyzes

Spain is one of the European countries where the population goes the most to the doctor, an average of 7.5 visits per inhabitant and year. This overuse also means undergoing numerous tests, such as clinical tests. In our country there is also the circumstance that periodic health control through analytical and medical tests is fully accepted at the social level .

This attitude towards health has created us a sometimes illusory dependence, since misinterpretations of the value of analytics in medical diagnosis are often given as results, and what is worse, health problems are created in many cases where really they did not exist.

A diagnostic aid, but not the basis

The results of medical tests can be representative and reflect our state of health, but they should always be interpreted from the perspective of the patient, the physician and the analyst. Before an analysis, the possibility of false positives and negatives, errors in the interpretation of the data, etc. must always be considered .

And the clinical history itself and the patient’s condition are always more important than the analytical data themselves. In all cases, the usefulness and importance of each test must be assessed.

Relativize the results

It is important not to forget that a medical analysis fulfills the function of being only a complementary diagnostic tool and a reference in what is a good clinical history. The results must be delimited, relativizing them and observing the positive side for the doctor and the patient.

Sometimes, after an examination and multiple analyzes and x-rays, the patient is told: “everything has been negative, you have nothing”, but this is of little use to a person who feels or thinks he is ill.

For a good diagnosis it is logical to follow a system and a method; Now, intuition, the clinical eye, must never be forgotten, which does not come through infused science, but through medical practice with the sick. The medical history is the own account of the disease. If we know how to ask, the patient will tell us about his disorders, he will unwittingly give us symptoms for a diagnosis.

Everything else, including analytics, is a benchmark to assess. In addition, it must not be forgotten that symptoms and signs produce much more powerful tests of diagnostic hypotheses than those that can be derived from diagnostic tests. Therefore, a greater use of diagnostic tests should not be associated a priori with higher quality of care or better health.

Automated techniques and quality controls

The laboratory tests are the most commonly used diagnostic tests. This use is not without controversy, which is facilitated by two factors: first, the technological development of the field of clinical analysis, which with the introduction of new tests and automated techniques has “democratized” its access, making them not only within reach of doctors but also of the patient.

An important phenomenon since it has led to an often excessive use of these tests in our country. The second is the ability to perform thousands of analyzes automatically in laboratories, each with its own technology, so quality controls should be required.

When is it really useful to perform an analytic

Furthermore, the usefulness and practical applicability of these laboratory tests vary according to the setting in which they are used and their purpose. A test as a form of detection in an asymptomatic population is not the same as to confirm or rule out a suspected diagnosis or control the evolution of a previously diagnosed health problem.

It is important to clarify very well if the test is going to be useful to us to better treat the patient, to help him with his problem, or we are going to complicate his life. Three types of tests can be distinguished: as a detection system, as a system for confirming a suspected diagnosis, and as a routine control system .

In the first case, screening refers to applying the test to a population that is assumed to be healthy. The application of the biochemical profile as a detection system in this case has been widely questioned. The recommendation is that detection by biochemical profiles is not used to find a hidden disease while the laboratory that has just produced the last test to, for example, locate a tumor is already advertising to recommend it to the entire population.

The second is a test that is used as a confirmation system for a suspected diagnosis. Unlike the healthy patient screened for a specific problem, the symptomatic patient often needs more than one test to differentiate between possible causes and establish the diagnosis. The third, finally, is a test used as a mere periodic control system .

It is about the evolutionary control of an already diagnosed health problem and the assessment of the response to treatment. It is one of the most important applications of laboratory tests.

Avoid overdiagnosis and overtreatment

Carrying out all kinds of tests and analyzes with the intention of looking for problems has turned out to be a frequent medical and social problem in our health system and has given rise to a medical movement called quaternary prevention, which aims to avoid overdiagnosis and overtreatment in the patients.

With this type of prevention, the consequences of the activity and the unnecessary or excessive use of the health system are also avoided or mitigated . Quaternary prevention identifies those patients at risk of overmedicalization to protect them from new medical practices. Actions are carried out to identify patients at risk of overtreatment.

Some medications or physical exercise are factors that can alter the medical tests.

At its core it is neither more nor less than putting into practice the ancient Hippocratic recommendation primum non nocere. This Latin expression translates as “the first thing is to do no harm” and it is a maxim applied in the field of medicine, attributed to the Greek physician Hippocrates.

Most of the time, when drugs are prescribed or therapeutic measures are applied, there is a possibility of side effects or harm to the patient. Quaternary intervention acts to protect them from new medical interventions and to suggest ethically acceptable alternatives.

Quaternary prevention leads to the provision of necessary care with the least possible intervention (with low intensity care and high therapeutic quality).

When uncertain conclusions are drawn from tests

An example of this abuse of overdiagnosis and overtreatment from the perspective of genetic analysis that abounds today would be screening for hemochromatosis, a common genetic disease.

In European populations, 10% are heterozygous carriers, and up to five per thousand are homozygous. Of what use is it to homozygotes to know a priori about their disease if it is not possible to predict who will develop the disease out of every 100 diagnosed?

Likewise, the determination of suppressor genes related to breast cancer leads to decisions such as mastectomy and preventive radical bilateral ovarectomy. In general, the predictive value of genetic testing is low due to the variable expression of genes and their different and changing degree of penetration and imprinting.

Due to its impact on health, maximum rigor should be demanded from genetic diagnostic tests and all the rest. Otherwise, patients may be exposed to diagnostic activities of dubious utility.