Vivian Granger

Reduction of intra‐ and interlaboratory variation in CD34+ stem cell enumeration using stable test material, standard protocols and targeted training

The European Working Group on Clinical Cell Analysis (EWGCCA) has, in preparation for a multicentre peripheral blood stem cell clinical trial, developed a single‐platform flow cytometric protocol for the enumeration of CD34+ stem cells. Using this protocol, stabilized blood and targeted training, the EWGCCA have attempted to standardize CD34+ stem cell enumeration across 24 clinical sites. Results were directly compared with participants in the UK National External Quality Assessment Scheme (NEQAS) for CD34+ Stem Cell Quantification that analysed the same specimens using non‐standardized methods. Two bead‐counting systems, Flow‐Count and TruCount, were also evaluated by the EWGCCA participants during trials 2 and 3. Using Flow‐Count, the intralaboratory coefficient of variation (CV) was ≤ 5% in 39% of the laboratories (trial 1), increasing to 65% by trial 3. Interlaboratory variation was reduced from 23.3% (trial 1) to 10.8% in trial 3. In trial 2, 70% of laboratories achieved an intralaboratory CV ≤ 5% using TruCount, increasing to 74% for trial 3; the interlaboratory CV was reduced from 23.4% to 9.5%. Comparative analysis of the EWGCCA and the UK NEQAS cohorts revealed that EWGCCA laboratories, using the standardized approach, had lower interlaboratory variation. Thus, the use of a common standardized protocol and targeted training significantly reduced intra‐ and interlaboratory CD34+ cell count variation.

Flow rate calibration I: A novel approach for performing absolute cell counts

Reports suggest that flow rate (FR) is constant on bench top flow cytometers. Therefore, if FR is constant, the volume acquired in a fixed time period will also be constant, enabling absolute leucocyte counting using flow rate calibration (FRC).

Flow rate calibration II: A clinical evaluation study using PanLeucoGating as a single‐platform protocol

CD4+ T‐lymphocyte enumeration is vital for monitoring disease progression in individuals positive for the human immunodeficiency virus (HIV), and as a result, there is a need to develop cost‐effective protocols that provide accuracy, precision, and affordability. Recently, PanLeucoGating has been shown to fulfill these requirements; however, although comparable to state‐of‐the‐art single‐platform protocols (SP), there is still a requirement for an accurate total white cell count. To overcome this limitation, we recently developed a flow‐rate based calibration method that enables the PanLeucoGating protocol to be used as a SP approach, and in this study show that this approach can be used for CD4+ T‐lymphocyte enumeration.

The United Kingdom National External Quality Assessment Scheme gating and standardization strategy for use in residual WBC counting of WBC‐reduced blood components

BACKGROUND : Major causes of interlaboratory variation in low‐level WBC counting are the gating strategies and staining methods employed. To overcome these limitations, a stable low‐level WBC control preparation (termed daily run control [DRC]) was developed that when coupled with a new gating strategy will enable international standardization.

Long-term stabilized blood samples as controls for flow cytometric HLA-B27 screening: a feasibility study.

Long‐term stabilized blood samples are potentially useful as positive or negative procedure controls for flow cytometric HLA‐B27 screening, and could serve as test samples in an external quality assessment (EQA) scheme. We evaluated long‐term stabilized whole blood specimens as prepared for the UK NEQAS for Leucocyte Immunophenotyping EQA scheme (Sheffield, UK).