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To understand left shift, you need to understand a little bit about the White blood cells and how they are formed. White blood cells are the police of the body and protect the body from harm. The WBC are produced by the hematopoietic cells of the body such as the Bone marrow or the Liver depending on your age. Adults mostly produce blood in bone marrow of long bones.
Now, the WBC grow similarly to humans. WBC will gradually grow and mature from a baby to an adult in the body. This can be in terms of size and some features. The best way to describe it would be to say immature to mature WBC. The biggest differentiating point between mature and immature WBC (most commonly neutrophils) is the nucleus. A single nucleus indicates immaturity and a segmented nucleus indicates maturity.
In the left shift, there are both immature and mature neutrophils present. This is not too important to us and is only the theory part. The practically important part are the causes of left shift. Here are a few of them:
Infections - most commonly bacterial infections
Necrosis - like in heart attacks or bowel infarct (rare and will have chest pain or abdomen pain)
Any condition that can lead to leukocytosis or release of cytokines
There is another condition known as leukoerythroblastotic reaction in which nucleated red blood cell are seen along with the left shift. This occurs when hemoglobin is low and the body begins to send out immature or nucleated RBCs. The implications to health are not much as the causes are transient and can be cured quickly.
Do not worry and if you are not feeling better after 3 days, see a Doctor.
Wishing you the best of health.
These Q&A’s are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.