“Segs” is a term frequently seen on blood test reports, specifically within a Complete Blood Count (CBC). Understanding “segs” helps individuals interpret their health information, offering insights into the body’s immune status and its ability to respond to various challenges.
What Are Segs?
“Segs” is shorthand for segmented neutrophils, a primary type of white blood cell (leukocyte). These cells are crucial components of the innate immune system, serving as a first line of defense against foreign invaders. Segmented neutrophils have a multi-lobed nucleus, which aids their movement through tissues to reach infection sites. They are the most abundant white blood cell in healthy adults.
The main function of segmented neutrophils involves identifying and destroying harmful microorganisms, particularly bacteria and fungi. They do this by engulfing and digesting pathogens through phagocytosis. These cells can also release antimicrobial substances and neutrophil extracellular traps (NETs) to neutralize threats and contain infections.
Normal Ranges and Their Significance
The typical reference range for segmented neutrophils in a healthy adult can be expressed as a percentage of total white blood cells or as an absolute count. Generally, they constitute 40% to 60% of the total white blood cell count. In absolute numbers, a normal range is often considered to be between 1,600 and 8,000 neutrophils per microliter of blood.
These ranges can vary slightly depending on the specific laboratory and individual factors. Knowing these normal ranges provides a baseline for healthcare providers to assess immune health. Deviations from these levels can signal the body’s response to various physiological states or potential underlying health issues, prompting further investigation.
Elevated Segs
When segmented neutrophil levels are higher than normal, the condition is called neutrophilia. This often indicates the body is actively responding to a threat or stressor. The most common cause is a bacterial infection, as neutrophils are the primary white blood cells dispatched to fight such pathogens. The immune system ramps up production and release of these cells from the bone marrow to combat the infection.
Beyond infections, various inflammatory conditions (like rheumatoid arthritis or inflammatory bowel disease) and tissue damage (such as burns or trauma) can also lead to elevated segmented neutrophil counts. Certain medications, particularly corticosteroids, can increase neutrophil levels by influencing their release into the bloodstream. Physical or emotional stress, vigorous exercise, and acute events like a heart attack can temporarily raise segmented neutrophil counts as part of the body’s physiological response. Certain cancers, including leukemias, can also result in increased neutrophil production.
Reduced Segs
A lower-than-normal level of segmented neutrophils is known as neutropenia. This reduction can compromise the body’s ability to effectively fight infections, particularly bacterial ones, increasing susceptibility. A common cause of reduced segmented neutrophils is viral infections, such as influenza or HIV, which can temporarily suppress bone marrow production or lead to increased destruction of these cells.
Certain medications, including chemotherapy drugs, can significantly lower neutrophil counts as a side effect, by affecting the bone marrow’s ability to produce blood cells. Bone marrow disorders, such as aplastic anemia or myelodysplastic syndromes, directly impair neutrophil production, leading to chronically low levels. Autoimmune diseases, where the body’s immune system mistakenly attacks its own healthy cells, can also target and destroy neutrophils. Severe or overwhelming infections can sometimes deplete the body’s neutrophil reserves faster than they can be produced. Nutritional deficiencies, such as those in vitamin B12, folate, or copper, may also contribute to neutropenia by impacting blood cell formation.