Hemolysis
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Hemolysis (or haemolysis)—from the Latin Hemo-, 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).
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In vivo hemolysis
In vivo hemolysis can be caused by one of a large number of diseases. Anemias caused by in vivo hemolysis are collectively called hemolytic anemias.
In vitro hemolysis
In vitro hemolysis can be an important unwanted effect in medical tests and can cause inaccurate results, because the contents of hemolysed red blood cells are included with the serum. The concentration of potassium inside red blood cells is much higher than in the serum and so an elevated potassium is usually found in biochemisty tests of hemolysed blood. If as little as 0.5% of the red blood cells are lysed the serum will have a visually obvious pinkish colour, due to hemoglobin.
In vitro hemolysis can occur in a blood sample owing prolonged storage or storage in incorrect conditions. Hemolysis can also occur at the time of venipuncture, but it is uncommon when the venipuncture is straightforward and the phlebotomist is experienced. Excessive suction can cause the red blood cells to be literally smashed on their way through the needle owing to turbulence and physical forces. Such hemolysis is more likly 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.
Hemolysis due to mechanical blood processing during surgery
In some surgical procedures (i.e. some heart operations) where substantial blood loss is expected, machinery is used for intra-operative blood salvage—essentially hemolysis occurring outside of the body. A centrifuge process takes blood from the patient, washes the RBC's with normal saline, and returns them to the patient's blood circulation. Hemolysis may occur if the centrifuge rotates too quickly (generally greater than 500 rpms). Unfortunately, haemolysis occurs with massive amounts of sudden blood loss, because the process of returning patient's cells must be done at a correspondingly higher speed to prevent hypotension, pH imbalance, and a number of other hemodynamic & blood level factors.
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Template:Medical-stubde:Hämolyse es:Hemólisis fr:Hémolyse it:Emolisi ja:溶血 nl:Hemolyse no:Hemolytisk anemi sv:Hemolytisk anemi tr:Hemoliz zh:溶血反應