Immature Granulocytes

The Immature Granulocytes Blood Test assesses the presence of a subtype of immature white blood cells in the bloodstream called granulocytes.  

This test provides crucial insights into the body's immune response and can aid in the diagnosis and monitoring of various medical conditions, including infections, inflammatory diseases, and bone marrow disorders.

 Understanding the significance of immature granulocytes and knowing when to order this test is essential for healthcare providers to effectively manage patient care. In this article, we will delve into the intricacies of the Immature Granulocytes Blood Test, including its procedure, clinical significance, and implications for patient management

Understanding Immature Granulocytes

What are Immature Granulocytes?

Granulocytes are a type of white blood cell that contains granules when viewed under a microscope.  The granules typically contain enzymes that are released in the presence of infections or allergens, and in asthma.  [7.]

Neutrophils, eosinophils and basophils are granulocytes because they are the types of white blood cells that contain granules.  

Typically, granulocytes develop in the bone marrow in a process called leukopoiesis and are released into the bloodstream when fully developed.  An immature granulocyte is an incompletely developed granulocyte that was released from the bone marrow early in response to allergy or infection, or another inflammatory condition.  [9.]

When these immature white blood cells are released into the bloodstream early, they are known as blasts, promyelocytes, myelocytes, and metamyelocytes.  Understanding the type of immature granulocyte that is elevated in the bloodstream is of clinical importance in determining the cause. 

What is the Significance of High Immature Granulocytes in Blood Test Results?

There can be many reasons for a finding of high immature granulocytes in a blood test.  

The presence of immature granulocytes in a blood test typically indicates an increased demand for white blood cells to combat infection or inflammation within the body.  In other cases it may indicate a cancerous or myeloproliferative disorder.

Healthcare providers often use this information to help diagnose and monitor various conditions including bacterial infections, sepsis, inflammatory disorders, and certain types of cancers.

It is increasingly considered an early and accurate marker for inflammation and infection.  [2.]

In the setting of infection, an elevated count of immature granulocytes is called a “shift to the left”.  It suggests that the bone marrow is releasing these immature cells into the bloodstream at a higher rate than usual to bolster the body's defenses. 

The degree of left shift observed in the blood test can provide insights into the severity and progression of the underlying condition, guiding further diagnostic evaluations and treatment 

Overview of the Immature Granulocytes Blood Test

Blood Test for Immature Granulocytes

This test is typically run as part of a complete blood count, or CBC, with differential.  The CBC with differential does not require fasting, although it is commonly run in conjunction with other tests that may require fasting.  

The blood test for immature granulocytes involves obtaining a sample of blood from a vein, typically from the arm, using a needle and syringe or by pricking the fingertip for a capillary sample. 

The blood sample is then analyzed in a laboratory using automated hematology analyzers, which count and categorize different types of blood cells, including immature granulocytes.  Sometimes this test is done via microscopic assessment of a peripheral blood smear.

When the Test Should be Ordered

The immature granulocytes blood test is part of the complete blood count (CBC) test, and is commonly run as part of routine blood work.  

It may also be ordered by healthcare providers in various clinical scenarios including in emergency settings to evaluate the body's immune response and aid in the diagnosis of certain medical conditions. 

Some common indications for ordering the test include suspected bacterial infections, viral infections, inflammatory disorders, and certain types of cancer. Additionally, the test may be used to monitor the effectiveness of treatment in patients with ongoing infections or inflammatory conditions.

Interpreting Results

A finding of high immature granulocytes on lab testing is often called a shift to the left because it reflects an increase in the number of immature forms of white blood cells, especially immature neutrophils, suggesting an early response to infection or inflammation.  [5.]

The white blood cell pool is typically replenished multiple times a day, so a rise in immature granulocytes, commonly neutrophils, signifies the shift to the left because of the shift to using immature neutrophils.  

Alternatively, a rise in immature granulocytes may signal a cancerous process in the blood, especially when one type of non-neutrophil blood cell is elevated.  

While there can be different reasons for this finding of elevated immature granulocytes in the blood, the main causes are typically infectious, inflammatory, or due to cancer.

Other less-common causes of elevated immature granulocytes may also be discovered, and are covered below.  

Causes of High Immature Granulocytes

Infection: Acute bacterial infections, particularly those causing a rapid increase in white blood cell production, may lead to elevated immature granulocyte levels.

Inflammation: Conditions associated with significant inflammation or tissue damage, such as trauma, surgery, or autoimmune disorders, can trigger the release of immature granulocytes into the bloodstream.

Bone Marrow Disorders: Dysfunction of the bone marrow, such as leukemia, myelodysplastic syndromes, or other hematological malignancies, may result in the overproduction of immature granulocytes.

Medications: Certain medications including corticosteroids, granulocyte colony-stimulating factor (G-CSF), or chemotherapy agents, can stimulate the bone marrow to produce more white blood cells, including immature granulocytes.

Physiological Stress: Severe physical stressors such as acute illness, surgery, or trauma, may cause a temporary increase in immature granulocyte levels as part of the body's stress response.  [2., 6.]

Pregnancy: pregnancy may induce leukocytosis with no clinical significance.  [1.]

When to be Concerned about High Immature Granulocytes

High levels of immature granulocytes can be concerning when they indicate a significant immune response, such as in cases of severe infection or inflammation, or in the setting of a cancerous or myeloproliferative disorder.  

A finding of high immature granulocytes in an outpatient clinical setting may cause the healthcare provider to inquire into lifestyle factors including stress, as well as symptoms associated with infection, inflammatory processes, and/or symptoms of cancerous or myeloproliferative disorders.   

While a slight increase in immature granulocytes may be a normal response to infection or stress, persistently elevated levels, especially when accompanied by symptoms like fever, fatigue, or unexplained weight loss, may indicate a more serious underlying condition requiring further investigation and management. 

In such cases, it is essential to consult with a healthcare provider to determine the cause and appropriate course of action.

Treatment Options for High Levels of Immature Granulocytes

• Treatment of high immature granulocytes typically involves addressing the underlying cause or condition contributing to the elevated levels.

• Antibiotic therapy may be prescribed for bacterial infections, while antifungal or antiviral medications may be necessary for fungal or viral infections, respectively.

• Intravenous fluids and supportive care may be administered to manage dehydration and maintain electrolyte balance in severe cases.

• Close monitoring of blood counts and regular follow-up appointments with a healthcare provider are essential to assess treatment response and adjust therapy as needed.

Tests for Immature Granulocytes

Click here for a list of tests that include immature granulocytes.