Effect of blood collection on its components How to protect blood Angry


When the sample is withdrawn from different sites, the blood components are also different. In the skin puncture, blood is more arterial than venous blood. Po2 and molecular pressure of PCO2 and oxygen saturation, while the molecular pressure of carbon dioxide in the veins is higher with a pressure of 6 to 7 mL Hg and blood glucose in the veins is about 7 mg / 100 ml (0.39 mmol / L) In capillary blood as a result of human consumption For him.


Involving red blood cells by blood decomposition occurs within the in vivo, as well as in the test tubes Invitro This process can take place under many conditions and conditions including:

Because the membrane of the red cornea allows water to enter, the cell size changes according to the change of the osmotic medium. If the pellets are placed in a hypotonic solution, the water is carried into the cell, the cell is opened, the membrane is transformed and the microcellular channels are created allowing the passage of hemoglobin and other contents of the cell Cells.

2 - Dissolving blood is obtained in the following cases:

Acute anemia or acute hemolytic anemia, as well as in the case of jaundice in neonates Jaundice
B - increase of hemoglobin in the urine Paroxysmal hemoglobinuria

3 - blood analysis of the treatment of some drugs:

Some drugs cause decomposition of red blood cells, including Quinine, Phenacetin, Nitrites, Chlorates,

4 - fatty solvents

Such as alcohol, ether, chloroform and some substances such as soap, yellow salts and sapponin saponin. These substances dissolve fat in the red membrane or change the directions of the arrangement of lipid molecules in the cell membrane

5 - Mechanical methods

Mechanical methods play an important role in the negative effect on different samples, especially blood samples. These methods are Grinding, Stirring, Shaking, and Thawing

There are also other factors that lead to the breakdown of blood in the tubes such as change in temperature and pH and exposure to ultraviolet light. The concentration of serum components of the hemoglobin concentration in the sickle sample is affected to more than 20 mg / 100 ml and there are two degrees of decomposition of the blood sample, Slightly Hemolysis has little effect on most chemical analyzes, and the second type is Hemolysis, which affects the dilution of components that are found in a small concentration of red blood cells rather than on plasma components. Intracellular in-vitro and extracellular concentrations such as sodium, potassium, LDH, etc.). On the whole, the apparent effect can be observed on the components present in plasma. Therefore, plasma concentration increases in the decomposing sample in the following tests: Aldolase and phosphatase Alkali, LDH, and isostretase extracting hydrogen, potassium, magnesium and phosphates. Inorganic phosphate increases in serum rapidly, such as the organic esters found in cells that are decomposed, and also increases the activity of enzymatic transgene (GOT, GPT) by 2% 10 mg / 100 ml of the increase in the concentration of hemoglobin and the enzyme LDH increases by about 10% per 10 mg / 100 ml of hemoglobin, and we can know the blood sample decomposed by looking at the naked eye.

Save blood

It is always preferable to perform analyzes as soon as possible and when storing all samples are kept after separation of the serum or plasma is cooled for the purpose of delaying the chemical reactions and thus prevent the change of the proportions of the components and the temperature suitable for conservation from 2-4 m, where few changes in this degree during several hours Of the left in the refrigerator and keep blood samples for the analysis of sugar and peruvite after the addition of a preservative.

When storing the samples for a long time to measure the enzymes, for example, it should be frozen at a temperature (-20 m) after the separation of the serum as soon as possible and prefer to divide the samples into small sizes before freezing to avoid the repetition of the process of melting and freezing again, leading to a fundamental change in the composition of proteins and enzymes and Perform the analysis Leave the sample to dissolve slowly at room temperature and then mix gently to obtain a homogeneous sample.

To collect blood samples it is recommended to follow the following precautions:

1 - It is preferable to collect blood samples from patients in the early morning and before breakfast only in special cases.

2. Check the tube where the blood will be placed and it should be dry as the presence of moisture leads to break the blood cells and make sure that the validity of the tube is not finished.

3. The type of treatment the patient is taking should be indicated

4 - The use of negative pressure should be avoided when blood is drawn, but blood is left flowing from the vein to the syringe slowly, and when the syringe is emptied into the preservation tube, it empties slowly to prevent the breakage of the blood cells.

5. The use of anticoagulants (coagulants) should not be overstated.

6. After the sample is withdrawn, it must be transported quickly to the laboratory. Keeping the blood at low temperatures leads to cell degradation and the distribution of ions in particular