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Hemolysis
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Hemolysis (or haemolysis)—from the Greek Hemo-, Greek meaning blood, -lysis, meaning to break open—is the breaking open of red blood cells and the release of hemoglobin into the surrounding fluid (plasma, in vivo).
n vivo (inside the body) haemolysis, which can be caused by a large number of conditions, can lead to anemia.
Anemias caused by in vivo haemolysis are collectively called haemolytic anemias.
a class="link1" onMouseover='showByLink("m238104",this)' onMouseout='hide("m238104")'href="http://www.absoluteastronomy.com/topics/In_vitro">In vitro (outside the body) haemolysis can be an important unwanted effect in medical tests and can cause inaccurate results, because the contents of haemolysed red blood cells are included with the plasma.
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Encyclopedia
Hemolysis (or haemolysis)—from the Greek Hemo-, Greek meaning blood, -lysis, meaning to break open—is the breaking open of red blood cells and the release of hemoglobin into the surrounding fluid (plasma, in vivo).
In vivo haemolysis
In vivo (inside the body) haemolysis, which can be caused by a large number of conditions, can lead to anemia.
Anemias caused by in vivo haemolysis are collectively called haemolytic anemias.
In vitro haemolysis
In vitro (outside the body) haemolysis can be an important unwanted effect in medical tests and can cause inaccurate results, because the contents of haemolysed red blood cells are included with the plasma. The concentration of potassium inside red blood cells is much higher than in the plasma and so an elevated potassium is usually found in biochemistry tests of haemolysed blood. If as little as 0.5% of the red blood cells are haemolysed the serum will have a visually obvious pinkish colour, due to haemoglobin.
Most causes of In vitro haemolysis are related to specimen collection. Difficult collections, unsecure line connections, contamination, and incorrect needle size, as well as improper tube mixing and incorrectly filled tubes are all frequent causes of haemolysis. Excessive suction can cause the red blood cells to be literally smashed on their way through the hypodermic needle owing to turbulence and physical forces. Such haemolysis is more likely to occur when a patient's veins are difficult to find or when they collapse when blood is removed by a syringe or a modern vacuum tube. Experience and proper technique are key for any phlebotomist or nurse to prevent haemolysis. In vitro haemolysis can also occur in a blood sample owing to prolonged storage or storage in incorrect conditions (ie too hot, too cold).
Haemolysis due to mechanical blood processing during surgery
In some surgical procedures (especially some heart operations) where substantial blood loss is expected, machinery is used for intraoperative blood salvage. A centrifuge process takes blood from the patient, washes the red blood cells with normal saline, and returns them to the patient's blood circulation. Haemolysis may occur if the centrifuge rotates too quickly (generally greater than 500 rpm)—essentially this is haemolysis occurring outside of the body. Unfortunately, increased haemolysis occurs with massive amounts of sudden blood loss, because the process of returning a patient's cells must be done at a correspondingly higher speed to prevent hypotension, pH imbalance, and a number of other haemodynamic and blood level factors.
Haemolysis in microbiology
Haemolytic patterns of the various Gram positive cocci; Streptococci are differentiated by haemolysis of red blood cells on blood agar (BA) plates.
- Alpha haemolysis is shown by a greenish halo around the colony and is the result of hemoglobin oxidation to methaemoglobin in red blood cells.
- Beta haemolysis is shown by a clear halo around the colony and is produced by complete hemolysis of the red blood cells.
- Gamma haemolysis is shown as no haemolysis or discoloration of the blood.
See also
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