(Toxic) shift to the left

In shift to the left, there is a relative increase of band neutrophils compared to segmented neutrophils. The ratio is usually around 1to 4 (rule of filament) or 1 to 12-15 (rule of one third). In severe bacterial infections neutrophilic abnormalities such as toxic granulation, vacuoles and Döhle bodies are typically designated as toxic.


Clinical picture:
The (toxic) shift to the left is not a clinical picture but rather a descriptive morphological term. This blood film abnormality normally occurs in bacterial infections as well as in other situations such as in burns, tumor lysis or acute inflammation (e.g. a gout attack).



A leukocytosis with neutrophilia is usually present, which is explained by an increased release of immature neutrophils from the bone marrow. The leukocyte count is normally between 10-20x109/L. It may, however, be higher in certain cases. The disappearance of eosinophils is also typical. Normal leukocyte counts associated with toxic conditions can be a sign of an exhausted granulopoiesis, which indicates a distinct increase in peripheral consumption of neutrophils, as may be seen in sepsis.