From the Guidelines
Bandemia is indicated on a complete blood count (CBC) by an elevated total band count of greater than 1500 cells/mm³ or a left shift with a percentage of band neutrophils of 16% or more, as these findings have the highest likelihood ratio for detecting documented bacterial infection 1. When examining a CBC report, look for terms like "bands," "band neutrophils," or "stab cells" in the differential count section. Key findings that suggest bandemia include:
- An elevated total band count (greater than 1500 cells/mm³)
- A left shift with a percentage of band neutrophils of 16% or more
- An elevated percentage of neutrophils (greater than 90%) These findings are often accompanied by leukocytosis (elevated total white blood cell count), though bandemia can occur with a normal or even decreased total white blood cell count. Bandemia represents a "left shift" in the maturation of neutrophils, indicating that the bone marrow is releasing immature cells in response to increased demand, typically due to infection, inflammation, or other physiologic stressors, as supported by studies such as 1 and 1. In clinical practice, the presence of an elevated WBC count or a left shift warrants a careful assessment for bacterial infection in any patient with suspected infection, with or without fever, as recommended by 1 and 1.
From the Research
Findings on CBC that Suggest Bandemia
- A band count >10% is indicative of underlying infection and is increasingly being used for early detection of sepsis 2.
- Elevated bands on an initial CBC were correlated with the likelihood of a concurrent bloodstream infection and in-hospital mortality, even at levels below 10% 3.
- Bandemia, even with normal total white blood cells, is associated with increased odds of having positive cultures, including blood cultures, and of in-hospital mortality 4.
- Severe bandemia (band level > 20%) is not associated with adverse outcomes in a general pediatric emergency department population 5.
Key Points to Consider
- Band counts should be considered in conjunction with other laboratory and clinical findings to guide diagnosis and treatment.
- The presence of bandemia may indicate the need for further evaluation, including blood cultures and other diagnostic tests.
- Clinicians should consider the overall clinical context, including history, physical examination, and other laboratory and imaging data, when interpreting CBC results 6.
- Increasing rates of bloodstream infections and in-hospital mortality are observed as band percentages increase, even at levels below 10% 3.