102 - Innovations on automated enumeration of immature granulocytes
Autor(s): E. Piva L. Pasini
Issue: RIMeL - IJLaM, Vol. 4, N. 3-S1, 2008 (MAF Servizi srl ed.)
Page(s): 102-103
The immature granulocytes (IG), normally absent from peripheral blood, are increased in conditions such as bacterial infections, acute inflammatory diseases, cancer (particularly with marrow metastasis), tissue necrosis, acute transplant rejection, surgical and orthopedic trauma, myeloproliferative diseases, steroid use, and pregnancy (mainly during the third trimester). Usually, automated instruments can enumerated only the five-type white blood cells (WBC) found in the peripheral blood. With improved technology, users and manufactures have started looking at new applications, including enumeration of cell types normally not found in the blood, or present at very low level as immature granulocytes. Our study aims to assess the information provided by new technologies, also considering dysplastic features of the IG. Correlation between the different methodologies, imprecision, and accuracy in comparison with the manual morphology count and with a flow cytometric count were evaluated. The preliminary assessment does not show encouraging results. The correlation between different instruments shows a value of r2 ranges from 0.11 to 0.44. Published studies agree that IG counts have a high specificity for infectious conditions (from 83% to 97%) but are accompanied by low sensitivity (between 35% and 40%). This low sensitivity does not allow to use the counting with the purpose of screening or early infection detection, while the clinical use in the evaluation of therapeutic response (e.g. to antibiotic therapy) seems more appropriate. At present, IG counting should not appear in the haematological report and must be used as a benchmark instrument-specific decision-making rules for reviewing or to be used in interpretative reporting for patients with clinically recognized infections.