Left shift (medicine)
Left shift or blood shift is an increase in the number of immature leukocytes in the peripheral blood, particularly neutrophil band cells.[1]
Less commonly, left shift may also refer to a similar phenomenon in severe erythroanemia, when reticulocytes and immature erythrocyte precursors appear in the peripheral circulation.[2]
Definition
The standard definition of a left shift is an absolute band form count greater than 700/microL.[3] There are competing explanations for the origin of the phrase "left shift," including the left-most button arrangement of early cell sorting machines[4][5] and a 1920s publication by Josef Arneth, containing a graph in which immature neutrophils, with fewer segments, shifted the median left.[6]
Morphology
It is usually noted on microscopic examination of a blood smear. This systemic effect of inflammation is most often seen in the course of an active infection and during other severe illnesses such as hypoxia and shock. Döhle bodies may also be present in the neutrophil's cytoplasm in the setting of sepsis or severe inflammatory responses.[7]
Pathogenesis
It is believed that cytokines (including IL-1 and TNF) accelerate the release of cells from the postmitotic reserve pool in the bone marrow, leading to an increased number of immature cells.[1]
See also
References
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- ↑ http://medicineoutofthebox.com/2010/10/26/the-meaning-of-a-shift-to-the-left/
- ↑ http://www.pathologystudent.com/?p=318
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- ↑ Lua error in package.lua at line 80: module 'strict' not found.
