From the Guidelines
No, not all patients with elevated immature granulocytes (IG) require immediate referral to hematology. The decision to refer should be based on the clinical context and the presence of other concerning features. Immature granulocytes can increase in response to various benign conditions such as acute infections, inflammation, tissue damage, or physiologic stress, a phenomenon known as a "left shift" 1. This is often transient and resolves once the underlying cause is addressed.
Key Considerations for Referral
- Significant elevation of IG (typically >10%)
- Persistence without a clear cause
- Accompanying severe anemia, thrombocytopenia, or blasts
- Clinical suspicion for hematologic malignancy In cases where the elevation is mild to moderate and there's an identifiable cause (e.g., bacterial infection, trauma, surgery, pregnancy), treating the underlying condition and monitoring with a repeat complete blood count after resolution is often appropriate. Hematology referral is warranted if the IG elevation persists after treating the apparent cause or if additional concerning symptoms develop, such as unexplained bleeding, bruising, or lymphadenopathy. The general principle is to refer patients with unexplained cytopenias or other hematologic abnormalities that could indicate a more serious underlying condition, as suggested by consensus recommendations 1.
From the Research
Immature Granulocytes and Referral to Hematology
- The decision to refer patients with elevated immature granulocytes (IG) to hematology depends on various factors, including the underlying cause of the elevation and the presence of other clinical symptoms or laboratory findings.
- Studies have shown that elevated IG counts can be associated with infection, sepsis, and myeloid neoplasms 2, 3, 4.
- For example, a study published in the American Journal of Clinical Pathology found that a percentage of immature granulocytes of more than 3 was a very specific predictor of sepsis 2.
- Another study published in the Journal of Hematopathology found that IG parameters assayed by the Sysmex XN hematology analyzer were helpful for screening of myeloid neoplasms, with a good performance of IG# and IG% for distinguishing between patients with myeloid neoplasms and those without 3.
Clinical Significance of Immature Granulocyte Counts
- Elevated IG counts can be a marker of acute inflammation, and studies have shown that they correlate with other inflammation markers such as C-reactive protein and erythrocyte sedimentation rate 5.
- However, the clinical significance of IG counts can vary depending on the clinical context, and further evaluation is often needed to determine the underlying cause of the elevation.
- For example, a study published in the Journal of Clinical and Experimental Hematopathology found that CD56 expression can be seen in normal immature granulocytes after allogeneic hematopoietic stem cell transplantation, highlighting the need for careful interpretation of IG counts in different clinical settings 6.
Referral Criteria
- Based on the available evidence, referral to hematology may be considered for patients with elevated IG counts who also have other clinical symptoms or laboratory findings suggestive of a myeloid neoplasm or other hematological disorder 3.
- However, the decision to refer should be made on a case-by-case basis, taking into account the individual patient's clinical presentation and laboratory results.
- Further studies are needed to establish clear referral criteria and to determine the optimal use of IG counts in clinical practice 2, 4, 5.