What are the types of blood tests, what blood tests results are in normal limits:
How are blood tests done. Human blood is composed of two essential elements: the liquid consisting of water, soluble in organic and inorganic substances and the solid composed of cellular elements (red cells, white cells and platelets). In case the blood is taken from the patient vein and it is placed in a test tube it coagulates itself after a few minutes. Then it is separated into a liquid layer, superior, called serum and a lower layer, which is a solid clot. If in the tube in which a substance was collected we add anticoagulant blood (which prevents clotting) then the blood no more coagulates, but still separate into two layers: the liquid upper layer consisting of plasma and the lower layer , solid, consisting of coagulated cellular elements. From these two components serum and blood plasma it will performed the main biochemical and serological medical tests. From cellular blood elements are made hematology analysis. Hematology analyzes the number, shape, and the composition characteristics of cellular elements of the blood.
Hematocrit: is the mass of red blood cells of a certain volume of blood. Normal hematocrit values are: men = 40-48% ; in women = 36-42%, children 2-15 years = 36-39%.
Hemoglobin: The red color of blood or red blood cells is given by a chemical that contains an iron-based pigment called hemoglobin. This substance has the ability to fix atmospheric oxygen in the lungs and then transport it throughout the body to the cells. Normal hemoglobin values: in men = 13 to 16 g per 100 ml of blood, in women = 11 to 15 g per 100 ml of blood.
Erythrocytes count : Red blood cells can be counted under a microscope. This requires a drop of blood taken from a finger or vein. The counting is done on a very small volume of blood, and the result is reported to 1 cubic mm of blood. Normal levels of red blood cells: men = 4.2 to 5.6 million per 1 mm cube, women = 3.7 to 4.9 million per 1 mm cube, children (1-5 years) = 4.5 to 4.8 million per 1 mm cube.
White blood cell count: The technique of counting white blood cells (WBC) is the same as for the red blood cells but number of leukocytes from human blood is much smaller. Normal levels of white blood cells: adults = 4000-8000 per 1 mm cube, children (1-6 years) = 1 mm per cubic 4000-1000.
Leukocytes formula : White blood cells are not all the same, they vary in shape, structure and functions. Depending of the way they are colored with dyes have been described several types of white blood cells, each with a specific role and significance in the body.
Platelets count: Platelets are smallest elements of blood solids and have the important role in coagulation (clotting) of blood. In case of bleeding in the blood vessel injury, platelets gather in oodles and contributes, among other mechanisms to clot formation and wound closure and therefore they stop the bleeding. Normal values of platelets: 150 000-300 000 / cubic mm.
Clotting time : a drop of blood from the fingertip is put it on a glass slide and we measure the time that has passed till the blood clotting. The normal coagulation time value is 8-12 minutes.
Bleeding time : It is an analysis that is performed to research the clotting power. Normal values of bleeding time: 3-4 minutes.
Howell time or plasma recalcification time : The analysis is done when your doctor suspects blood clotting disorder especially after a treatment with anticoagulants. Normal values of Howell time: 60-120 seconds.
Quick time or prothrombin time: it explores the clotting ability of blood. Normal values of Quick Time: 12-15 seconds or 80-100%.
Speed erythrocyte sedimentation rate : It’s a simple analysis that relies on the property of red blood cells to sediment. Normal values of erythrocyte sedimentation rate: men = 10.3 mm at a time; 5-15 mm to 2 hours, in women = 6-13 mm at a time; 1-20 mm to 2 hours, in infants = 7-11 mm at a time.
Analysis of blood group: Red blood cells (erythrocytes) in human blood differs from immunologically point of view. They differ from one person to another by the presence or the absence of specific chemicals that are found both on the erythrocyte surface and in blood serum. Based on these differences in blood composition, people were divided into several groups blood. But usually, laboratory analyzes only two systems of blood groups: Rh system and OAB system.
Before blood tests:
Some seemingly minor errors, such as food intake or administration of drugs before performing medical tests are sufficient to compromise the results. Eating less than 14 hours before blood tests will always compromise laboratory test values, especially cholesterol and blood sugar. Birth control pills, estrogen, anticonvulsants, regulate blood pressure medicines, diuretics, corticosteroids, antidepressants or niacin (vitamin prescribed to lower cholesterol) are substances that always interfere with the results of a blood test If you are in a period of physical stress caused by an acute illness or an infection, blood tests will register lower levels of good cholesterol HDL and high triglycerides. If blood tests aim to measure glucose and lipid levels, only the water is allowed to consume 14 hours before performing blood tests. Avoid chewing gum, including sugar-free varieties, before a blood test. They can have the same effect of compromising blood tests as food consumption. Any form of exercise is prohibited with 8 hours before the blood tests because exercises change the real level of glucose in blood. The substances in cigarettes come quickly into the bloodstream, so smoking is strictly forbidden at least 14 hours before blood tests. Vitamins, minerals and herbal supplements should be avoided before blood tests, especially if we want to measure the lead level in blood.
This blog post is an educational resource only and does not replace a medical consultation with a doctor .
Please feel free to get in touch if you have any questions or comments. Your feedback welcome!