When carrying out any diagnostic measures, the results of the research are considered comprehensively. In this case, all indicators are taken into account: the general condition of the patient, the nature of the course of the pathology, symptoms.
Quantitative and qualitative research
The results of a number of laboratory tests are issued to patients in the form of "positive" or "negative". This form is considered a qualitative characteristic. An example is an analysis for antibodies to a particular infection. A positive result indicates the presence of these antibodies in the material.
What does "reference value" mean?
In the quantitative type of study, the results are given in the form of numbers. In this case, there is a range of norms, as well as averages. Reference value in analysis is a medical term used to evaluate the results of laboratory tests. It is defined as the average value of a certain indicator. These data are obtained by examining the he althy part of the population. To begin with, we can consider some referencethyroid hormone values. For example, for free T3, values \u200b\u200bof 1.2-2.8 mIU / L will be normal, and for thyroxine (total) - 60.0-160.0 nmol / L. This is how the TSH analysis indicator may look like: the reference values \u200b\u200bare 0.5-5.0 μIU / ml, and the result itself is 2.0. As can be seen from the last example, the figure obtained during the study is in the normal range.
How are normal boundaries determined?
The only way, as mentioned above, is to examine he althy people. The first step is to sample the population. For example, he althy women are invited, whose age is from twenty to thirty years. Most of them are assigned to clinical trials. The results are reduced to average figures, calculating the range in which the reference values \u200b\u200bare. A deviation from the normal indicators (in one direction or another) by two standard units is allowed.
Why do different labs give different results?
Depending on the research method used and the means of measurement, one or another reference value is given. Different laboratories may use different equipment, use one or another unit of calculation. In accordance with this, the ranges of indicators are also set.
When receiving the result, the form must contain the numbers and units of measurement used in a particular laboratory. Thus, in medicine, for example, there are no single reference values for a blood test. Viewing Specialistresults should refer to the numbers used by the institution where the patient was examined. The difference can be seen by considering, for example, some reference values of a biochemical blood test. So, the range of indicators for ethylidene in the study by the G7PNP method is 28-100 U/l, and by the CNPG3 method - 22-80 U/l.
Why can indicators go beyond the norm?
The reference value in analysis is a statistical data, not a biological law. In some cases, there may be a deviation from the limits of the established ranges, even in he althy people. Than it can be caused? Among the many causes of deviations, the physiological characteristics of the organism are of particular importance. If the specialist recommends that the same laboratory test be performed several times, then there is a certain probability that a deviation from the normal limits will appear in the results. In accordance with biological reasons, indicators can change daily. To compare the results, the doctor prescribes tests again. As a rule, diagnostic conclusions are made not in accordance with single indicators, but in assessing the dynamics of changes. In he althy individuals, data may not fall within generally accepted ranges.
At the same time, for the people themselves, the results will be considered the norm. Such cases usually involve minor deviations. Nevertheless, indicators that do not fall within the reference values may indicate disorders in the body that require further diagnostic measures. specialist, evaluatingresearch results, takes into account the general condition of the patient, the clinical picture, studies the medical history and other factors. As a result, the doctor determines what the deviation from the normal numbers indicates.
What factors can influence research results?
The lab can give the patient the results according to their sex and age. For example, the reference values of creatinine (in the study of serum) in men under 50 years of age are 74-110 μmol / l, after 50 - 70-127 μmol / l. In women, the indicators are set regardless of age and are 60-100 µmol / l. The reference values of hCG for the fair sex depend on whether the patient is pregnant or not. The results of the studies may be affected by the treatment received, the features of the daily regimen and nutrition. Bad habits are also an important factor: smoking, alcohol or coffee abuse. Even the posture of the patient during the delivery of the material can affect the performance. For example, the content of calcium and albumin may increase when the position of the patient changes from horizontal to vertical. To obtain a more accurate result, before the study, the specialist may recommend excluding physical activity, stressful situations, quitting smoking and alcohol, taking medications and vitamins.
The effect of physical activity on results
It is not recommended to visit the gym on the eve of the study. Physical activity affects the enzymatic activity of creatine phosphokenase, lactate dehydrogenase,aspartate aminotransferase. Athletes who have been involved in weightlifting or athletics for many years may have elevated levels of luteinizing hormone, platelets, and testosterone. Given all these factors, you should follow certain rules before taking tests. When preparing for certain studies, the doctor, as a rule, gives special recommendations. If the patient follows the instructions of a specialist, then he is much more likely to get accurate and correct results.
Common misconceptions
There are several misconceptions about reference values and, in fact, research results. Many believe that deviations from the norm certainly indicate disorders in the body. However, this is not always the case. Results outside the generally accepted ranges indicate the need for further testing or reanalysis. It is likely that the result does not indicate a violation, but falls in 5% of cases in which abnormalities are observed in he althy people. In any case, the doctor will take the necessary measures to accurately assess the situation. As mentioned above, there are many factors that can affect the result. For example, high blood sugar may indicate not diabetes, but nutritional errors. Lipid levels rise if the test is not taken on an empty stomach. An increase in the content of liver enzymes may be associated with the use of alcohol on the eve of the study, and not with cirrhosis. Among other things,the results are also affected by the medications taken. Today, pharmaceutical companies produce a huge number of drugs. Laboratories sometimes simply do not have time to evaluate their impact on blood or other test material. In some cases, the values may return to normal on their own if they were on the border of the reference values.
Should I be concerned if test results are normal?
In general, such indicators are undoubtedly a good sign and indicate the absence of any disorders in the body. However, according to many experts, a certain set of studies does not guarantee the complete absence of he alth problems. In the statistical processing of reference ranges, there is always a partial coincidence of the results of people with pathologies and he althy people. In other words, in the latter, in the absence of disturbances in the activity of the body, the indicators may deviate from the norm. Similarly, in people with pathologies, test results may be within the normal range. To clarify the indicators, as a rule, repeated studies are prescribed after a certain period. When assessing the dynamics of changes, the specialist either notes the absence of violations or suspects any pathology. In the second case, additional examinations are prescribed to clarify the diagnosis.
