Lack of consensus in inter-laboratory haematology results in selected laboratories in the southern and northern zones of Ghana

Abstract

Objective: To assess the inter-laboratory comparability and intra-assay reproducibility of full blood count (FBC) results.

Design: Exploratory cross-sectional study.

Setting: Three and two selected medical laboratories in the northern and southern zones, respectively.

Participants: Forty-nine individuals per zone; 16 type 2 diabetes mellitus, 16 with HbAS haemoglobin type and 17 normal samples.

Intervention: Each sample was run eleven times through the analysers in the participating laboratories to evaluate intra-laboratory reproducibility and comparability of FBC results.

Main outcome measure: Intra-laboratory reproducibility was evaluated using %coefficient variation (%CV). Interlaboratory comparisons were assessed through t-test or One-Way ANOVA for two-sample and three-sample tests. All statistical testing was undertaken using the two-tailed assumption.

Result: Statistically significantly different haemoglobin levels were estimated in both northern and southern zones (mean difference 0.00 g/dL to 3.75 g/dL vs 0.18 g/dL to 1.92 g/dL respectively). Also, total WBC counts significantly differed across laboratories in both northern and southern zones (mean difference 0.15 ×10⁹/L - 3.86 ×10⁹/L vs 0.02 ×10⁹/L to 1.39 ×10⁹/L respectively). Furthermore, platelet counts significantly differed across the participating laboratories in the northern and southern zones (mean difference 0.40 ×10⁹/L to 299.76 ×10⁹/L vs 5.7 ×10⁹/L to 76.9 ×10⁹/L respectively). Moreover, there was evidence of non-reproducibility of results within the respective laboratories in each zone as the respective %CV were outside the acceptable limits.

Conclusion: The intra-laboratory non-reproducibility and inter-laboratory non-comparability of FBC results highlight the need to establish a national quality assessment scheme to harmonise laboratory practices nationwide.

Funding: This study was funded by the University of Cape Coast Individual-Led Research Support Grant (RSG-INDI-CoHAS-2019-107).

Keywords: External quality assessment scheme; intra-laboratory reproducibility; laboratory harmonisation.