Content area
Full Text
Key Words: nRBC; Automated nRBC count; Sysmex XE-5000
Am J Clin Pathol March 2016;145:379-384
DOI: 10.1093/AJCP/AQV084
ABSTRACT
Objectives: We validated the automatic nucleated RBC (nRBC) count on a Sysmex XE-5000 hematology analyzer (Sysmex Corporation, Kobe, Japan) and then evaluated the frequency of nRBCs in our patient population.
Methods: We correlated automated nRBC enumeration by the Sysmex XE-5000 hematology analyzer on 463 peripheral blood (PB) samples with the manual nRBC count. Results from 360,504 consecutive blood samples were reviewed to determine the frequency of nRBCs in various patient populations in our hospital.
Results: There was a strong correlation between the automated and manual nRBC count (Pearson's r ¼ 0.97). Frequency of nRBCs varied in different patient populations and was significantly higher in the presence of other morphology flags or abnormal CBC parameters. Low-level nRBCs (0.2%-1.3%) were detected in 0.5% of samples with otherwise normal parameters.
Conclusions: The automated method offers many advantages for high-throughput laboratories, including faster turnaround time, labor savings, and high reliability. Automated nRBC measurement allowed us to recognize a group of individuals who have low-level circulating nRBCs with otherwise normal CBC parameters. Nucleated RBC levels below 1.5% as detected by the automated count may be present in patients without increased erythropoiesis or a pathologic bone marrow process.
Peripheral blood (PB) smear examination remains one of the major nonautomated, labor-intensive procedures in the hematology laboratory. High-throughput laboratories continue to struggle with reducing the number of PB smear examinations while maintaining accuracy of the analysis. One common indication for a manual smear review is the detection of nucleated RBCs (nRBCs) by hematology analyzers.
Nucleated RBCs are immature erythrocytes that, under physiologic conditions, are most commonly seen during pregnancy and in the blood of neonates.1-3 Detection of nRBCs under other conditions is usually an indicator of a pathologic state associated with either increased erythroid activity or damage to the bone marrow microenvironment.4-9 In some clinical conditions, the presence of nRBCs has been linked to a worse prognosis.10,11 In addition, accurate nRBC enumeration is essential for correcting WBC counts, since nRBCs are often included together with lymphocytes in automated hematology analyzers.
Until recently, it was virtually impossible for hematology analyzers to distinguish a small mature lymphocyte from an nRBC. The only reliable method for nRBC...