What does a neutrophil count of 6.1 thousand per microliter (normal range) indicate?

Neutrophil Count of 6.1 Thousand per Microliter: Interpretation and Clinical Significance

A neutrophil count of 6.1 thousand per microliter is within the normal range and does not indicate any pathological condition when considered in isolation. 1

Normal Range and Interpretation

• A neutrophil count of 6.1 × 10^9/L (6,100/μL) falls within the normal reference range for adults 1
• Normal neutrophil counts typically range from approximately 1.5 to 7.0 × 10^9/L, though exact reference ranges may vary slightly between laboratories 2
• This value represents a normal count of circulating neutrophils, which are the most abundant type of white blood cells and play a crucial role in the body's immune defense against infections 1

Clinical Significance

When No Further Evaluation Is Needed

• In the absence of symptoms, fever, or other clinical manifestations, a neutrophil count of 6.1 × 10^9/L does not require further investigation 1
• This value alone is not indicative of bacterial infection, as significant neutrophilia typically involves counts higher than this level, often accompanied by other clinical signs 1
• For comparison, in bronchoalveolar lavage fluid, neutrophilia is defined as greater than 3% neutrophils, but peripheral blood has different reference ranges 2

When to Consider Further Evaluation

• Further evaluation should be considered if the patient has:
  • Fever or other signs of infection 2
  • Specific symptoms suggesting a focal infection 1
  • Risk factors for neutropenia (e.g., chemotherapy, certain medications) 2
  • Other abnormal laboratory values or clinical findings 1

Special Considerations

Monitoring in Specific Conditions

• In patients with cirrhosis and ascites, neutrophil counts in ascitic fluid (not blood) greater than 250 cells/mm³ would indicate spontaneous bacterial peritonitis 2
• In cancer patients, neutrophil counts should be monitored regularly, especially during chemotherapy, as neutropenia (counts <1.5 × 10^9/L) increases infection risk 2
• In patients with hematologic malignancies like CLL, neutrophil counts should be monitored even if initially normal, as treatment and disease progression can affect counts 2

Variations in Normal Range

• Certain ethnic groups may have naturally lower neutrophil counts (benign ethnic neutropenia), particularly affecting 25-50% of individuals of African descent and some Middle Eastern ethnic groups 3
• Age can affect normal ranges - neonatal neutropenia is defined as counts below 2.0 × 10^9/L 4

Prognostic Significance

• Even within the normal range, higher neutrophil counts (6-7 × 10^9/L vs. 2-3 × 10^9/L) have been associated with increased risk of certain cardiovascular conditions including heart failure, peripheral arterial disease, and myocardial infarction 5
• Higher neutrophil counts can be predictive of complications following ST-elevation myocardial infarction 6

Conclusion

A neutrophil count of 6.1 × 10^9/L is within normal limits and, in the absence of symptoms or other abnormal findings, does not warrant further investigation. However, neutrophil counts should be interpreted in the context of the patient's overall clinical picture, including symptoms, other laboratory values, and medical history.