As a rule, a blood test is carried out once a year to check so-called routine parameters.
The aim of this examination is to check the function of organs such as the liver, kidneys and thyroid. In addition, the examination before operations, for the detection of diseases, preventive examinations but also for therapy control, e.g. used by determining drug levels.
Usually the written result of a blood test is difficult to understand for the layperson. Here you will find an overview of the most important parameters and their meaning.
Values in the blood test
There are many different values that can be determined with a blood test. In the following, the values are divided into main groups and the most important values of this group are then explained.
- General parameters: i.a. Electrolytes, kidney values and lipids
- Enzymes: mainly liver enzymes but also pancreatic enzymes
- Coagulation values
- Small blood count: cells of the blood
- Complete blood count
- Inflammatory factors
- Blood gas analysis
- Hormones: i.a. Thyroid hormones
- Drug levels
- Proteins: i.a. antibody
Sodium is a very important salt in our body. It influences the water balance and also plays a decisive role in nerve conduction. If the values deviate, seizures can occur. Decreased values can result from the use of diuretics, diarrhea or increased vomiting. 135-145 mmol / l is the normal value.
For more information, see our topic: Sodium
Potassium and sodium form an important antagonist in our body. While potassium is mainly found in the cell, sodium can be found outside.
A disruption of the potassium balance can cause life-threatening conditions. Potassium has the important regulatory functions on the heart and on the nerves. A potassium disorder can result in cardiac arrhythmias, muscle cramps or sensory disturbances. The framework values are 3.8-5.2 mmol / l.
Read more about this under the topic: Potassium
Calcium or calcium is important for blood clotting, as a signaling substance and also for building bones. Various organs and hormones are involved in the regulation of calcium, such as the small intestine, kidney, bones and especially the parathyroid gland. A lack of calcium can indicate a malfunction of the parathyroid glands. An increase in the values can be caused by a change in the parathyroid gland, kidney failure, vitamin D deficiency or bone tumors. Standard values are 2.02-2.60 mmol / l in total calcium.
More information can be found here: Calcium
Chloride is often tested routinely. There may be indications of a pH shift, i.e. over-acidification or alkalosis (shift in a basic direction). The normal value is 95-110 mmol / l.
Magnesium is used for diagnostics, as elevated levels can indicate kidney failure. Low values are usually found in cases of malnutrition, abuse of laxatives or an absorption disorder in the intestines or kidneys. The normal value is 0.7-1.0 mmol / l.
Read more about the topic here: Magnesium
Phosphate is particularly relevant for humans as a component of the energy carrier ATP. A deficiency can be associated with weakness and symptoms of paralysis and can be traced back to malnutrition, alcoholism or a vitamin D deficiency. As with magnesium, an increased value can be the cause of renal insufficiency. The value should be 0.84 to 1.45 mmol / l.
Urea, uric acid, creatinine and creatinine clearance provide information about the function of the kidney and its filtration properties. Urea should be between 20-45 mg / dl and creatinine between 0.8 and 1.2 mg / dl in women and 0.9-1.4 mg / dl in men. Elevated values can result from increased protein consumption, but can also be an indication of decreased kidney function.
Read on here: Kidney values
LDL and HDL
LDL (low density lipoprotein) and HDL (high density lipoprotein) are how the names indicate lipoproteins. These are responsible for the transport of insoluble fats in the blood. From the ratio of LDL and HDL it can be deduced whether there is an increased risk of arteriosclerosis due to increased fat levels in the blood. LDL is seen as a positive factor and HDL as a "bad" lipoprotein.
Read more about this under: LDL- low density lipoprotein and HDL- high density lipoprotein
The transaminases alanine aminotransferase (ALT) and aspartate aminotransferase (AST) are particularly important. When cells in the liver are damaged, these enzymes are released from the cells and can thus be a sign of inflammation of the liver, a liver tumor or alcohol abuse. The values for ALT should be below 23 U / l and for AST below 19 U / l at room temperature. Glutamate dehydrogenase is also one of the liver-specific enzymes. Elevated values can be found especially in severe liver inflammation, poisoning or liver cancer.
Further information on the subject can be found here: Liver values
The most important pancreatic enzymes are lipase, amylase and elastase. These often serve as an indicator when an acute inflammation of the pancreas is suspected, since in this case the enzyme concentration in the blood is increased. On the other hand, low values indicate a reduction in the function of the pancreas, which can also be caused by chronic inflammation of the pancreas.
Normal values are below 60 U / l for lipase and below 53 U / l for amylase.
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- Lipase level
INR and Quick value
The INR (Internationali Normailized Ratio) and the Quick value, also known as the thromboplastin time, exclude the duration of blood clotting and disorders of the extrinsic pathway (one of the two forms of blood clotting activity). A vitamin K deficiency or liver damage are possible causes of slowed coagulation. Among other things, the coagulation factors are produced in the liver. The Quick value is given in percent and should be between 70 and 100%. The INR should be around 1 and has no unit.
Partial thromboplastin time
The partial thromboplastin time (PTT) is a possibility to measure the second activation path of coagulation - the intrinsic pathway. If this time is prolonged, it can be a sign of haemophilia or other diseases with impaired coagulation. The PTT should be 26-36 seconds.
Small blood count
Erythrocytes, hemoglobin and hematocrit
The erythrocytes (red blood cells), hemoglobin and hematocrit are examined in a small blood count. The number of erythrocytes should be between 4.3 and 5.2 million / µl in women and 4.8-5.9 million / µl in men. If the number is low, there may be anemia, either due to blood loss or iron deficiency. An increase can be caused by stress, lack of oxygen or lack of fluids. Hemoglobin is the red pigment of the erythrocytes, which is also responsible for binding oxygen. Deficiency can also be related to iron deficiency. As a rule, the value should be 12-16 g / dl for women and 14-18 g / dl for men. The hematocrit is defined as the proportion of erythrocytes in the whole blood and should be 37-47% in women and 40-54% in men. The proportion is higher in the case of dehydration and smokers. In the case of pregnant women and blood loss, however, decreased.
The leukocytes (white blood cells) are also examined in a small blood count. They are an important parameter for inflammation, as they are part of the immune system and in this case occur in increased numbers in the blood. However, they are a non-specific indicator of inflammation. They can also be increased in allergies and gout, but the values are most serious in leukemia. Decreased values occur with virus infections. The normal value is 4-10 thousand / µl.
Platelets (platelets) are important for wound healing and blood clotting. If the number is reduced, there may be increased bleeding because the blood clotting is disturbed. 150-400 thousand / µl is the normal number.
Complete blood count
The complete blood count (differential blood count) differs from the small blood count only in that the white blood cells are also differentiated. Changes in the number and composition of granulocytes and lymphocytes can be detected, which allow a more accurate diagnosis. An example would be diseases of the rheumatic type, since eosinophilic granulocytes are more common here.
One of the most important inflammatory factors besides the already mentioned leukocytes is CRP (C-reactive protein). It is produced in the liver and increasingly released when there is inflammation or injury.Usually it should be below 0.5 mg / dL. In the case of minor injuries, it can also be around 40 mg / dl. Significantly increased concentrations that indicate inflammation or an infection are more relevant.
You might also be interested in this article: Inflammation levels in the blood - what do they indicate?
Blood gas analysis
In blood gas analysis, the partial pressures of the blood gases, especially oxygen and carbon dioxide, are determined. But also the bicarbonate concentration and the pH value are determined by it. A derailment of the acid-base balance can be determined and possible causes such as hyperventilation or kidney insufficiency can be concluded. Blood gas analysis is particularly important in the case of diseases of the lungs or heart.
In the case of thyroid hormones, a distinction is made between the actual hormones that are produced by the thyroid gland, such as thyroxine (T4) and T3 and the thyroid stimulating hormone (TSH), which is released by the pituitary gland to release the thyroid hormones. Hyperthyroidism and hypothyroidism are very common and are diagnosed primarily with blood values.
A distinction can also be made between primary and secondary disorders, depending on whether the hormone production in the pituitary or thyroid is disturbed.
Standard values for T4 are 2.2-5.5 pg / ml, for T3 0.6-1.8 ng / dl and 0.4-2.5 mU / l for TSH.
Read more about this: Hyperthyroidism such as Hypothyroidism
In addition to the thyroid hormones, hormones of the adrenal cortex such as cortisol, metabolic hormones such as insulin and the Sex hormones to be determined. The diagnosis is relevant, among other things, for Cushing's disease, diabetes, or if you want to have children.
In addition to checking laboratory values, the effectiveness of a therapy can be checked.
Cancer screening / early cancer detection can also be carried out by taking a blood sample. Many forms of prostate cancer (porate cancer) can be recognized in the blood for the first time by increasing a so-called tumor marker (PSA = prostate-specific antigen).
Laboratory values can change, especially when therapy with a drug is started. Some forms of therapy require regular blood counts. The therapy with Marcumar can be mentioned as an example. Here, the coagulation system is inhibited so that the blood becomes "more fluid". In order to check the effectiveness of the therapy, blood samples must be taken closely.
Please note that we do not claim to be complete or correct in any of our topics. The information may be out of date due to current developments.
We expressly point out that existing therapies may never be discontinued, started or changed independently and without consultation with your treating doctor.