Comparative Diagnostic Performance of the Granulocyte and Neutrophil Counts

Nicola S Pether,Jessica L Brothwood,Cornelis Van Berkel,Elaine H Dunwoodie,Robert L Blake,Christopher P Price,Richard G Jones,Karl S Baker,Geoff Hall

doi:10.1016/j.plabm.2017.10.001

Nicola S Pether, Jessica L Brothwood + Show 7 more

Open Access

https://doi.org/10.1016/j.plabm.2017.10.001

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Abstract

ObjectivesUse of point-of-care testing is increasing, however many haematology analysers can only determine granulocyte count without further differentiation into neutrophils, eosinophils and basophils. Since the diagnosis of life-threatening neutropenia in cancer patients requires a distinct neutrophil count, this study aimed to determine the comparative performance between the neutrophil and granulocyte count. Design and methodsA database of 508 646 venous full blood count results measured on a laboratory reference analyser was mined from a large oncology unit. The relationship between granulocyte and neutrophil counts was assessed. Multinomial logistic regression was used to classify results into neutropenia grades using an equivalent granulocyte count. ResultsGranulocyte to neutrophil count correlation was 0.997. The accuracy for classification into neutropenia grades using the derived equivalent granulocyte count ranges was 96.4%. Identification of results with a neutrophil count <1.5×109 cells/L using an equivalent granulocyte count of <1.69×109 cells/L resulted in sensitivity, specificity, positive and negative predictive values of 98.0%, 99.5%, 97.8% and 99.5%, respectively. ConclusionsThese results describe the relationship between granulocyte and neutrophil counts, measured on a laboratory analyser, in a large population of patients with malignancies and receiving anti-cancer therapies. However, this relationship must be established using a point of care testing system with a three-part differential count before considering the possibility that a granulocyte count can guide clinical decisions in the absence of a definitive neutrophil count, to reduce the frequency and severity of neutropenic complications in patients receiving cancer treatments.

Highlights

The technology of morphological assessment and counting of blood cells has advanced over recent decades, in the 1 these authors contributed .white cell lineage, with concomitant benefits in relation to diagnosis, prognosis and management of inflammatory and malignant conditions
187,003 (36.8%) results fell within the reference range for eosinophil, basophil and neutrophil results and there were 404,935 (79.6%) results within the upper limit of normal for all three granulocyte components
The Bland-Altman analysis indicated good agreement between granulocyte and neutrophil counts with 97.6% of granulocytes being within 0.265 × 109 cells/L of neutrophil counts when all neutrophil counts were less than 1.5 × 109 cells/L

Summary

Introduction

The technology of morphological assessment and counting of blood cells has advanced over recent decades, in the 1 these authors contributed .white cell lineage, with concomitant benefits in relation to diagnosis, prognosis and management of inflammatory and malignant conditions. Dependence on a service provided by a central laboratory has certain limitations, with potential clinical, operational and economic implications These issues could arise in any setting where rapid decision making is required, e.g. the Emergency Department, primary care, a paramedical rural service, an out-of-hours doctor service or in the home, as well as in middle- and low-income countries [1,2,3,4,5]. Most chemotherapy patients are given immediate empirical antibiotics upon suspicion of infection [14] In such patients, access to a rapid differential white count is vital as delays in administration of broad-spectrum intravenous antibiotics are associated with increased mortality risk, but overtreatment with unnecessary antibiotics has opportunity costs [15]

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