Effects of sample age and storage temperature on the flow cytometric diagnosis of chronic lymphocytic leukaemia in South Africa

Background: Chronic lymphocytic leukaemia (CLL) is a haematological neoplasm with characteristic flow cytometric immunophenotyping. Pre-analytical variables impact the quality and reproducibility of flow cytometric data, which could alter the diagnosis from CLL to atypical CLL (aCLL). Objective: Th...

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Main Authors: Shaun M. Grobler, Anne-Cecilia van Marle
Format: Article
Language:English
Published: AOSIS 2025-05-01
Series:African Journal of Laboratory Medicine
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Online Access:https://ajlmonline.org/index.php/ajlm/article/view/2688
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author Shaun M. Grobler
Anne-Cecilia van Marle
author_facet Shaun M. Grobler
Anne-Cecilia van Marle
author_sort Shaun M. Grobler
collection DOAJ
description Background: Chronic lymphocytic leukaemia (CLL) is a haematological neoplasm with characteristic flow cytometric immunophenotyping. Pre-analytical variables impact the quality and reproducibility of flow cytometric data, which could alter the diagnosis from CLL to atypical CLL (aCLL). Objective: This study investigated the effects of pre-analytical variables, specifically sample age and storage temperature, on the stability of key antigens used in the diagnosis of CLL. Methods: Serial flow cytometric analyses were performed from January 2022 to March 2023 on blood samples of 10 CLL patients from the Universitas Academic Hospital Haematology Clinic in Bloemfontein, South Africa. Samples were stored at room and refrigerator temperatures and analysed at baseline, 24 h, 48 h, 72 h and 96 h. We recorded the percentage and intensity of antigen expression of CLL makers, including CD5, CD20, CD23, CD79b, CD200 and sIgM, and assessed whether these affected the adapted and modified Matutes scores. Results: Statistically significant changes were observed in CD5 (p = 0.028), CD23 (p = 0.003) and CD200 (p = 0.005) expression, with better stability at refrigerator temperature. Two samples showed changes in both Matutes scores by 24 h, irrespective of storage temperature. By 48 h, scores changed to aCLL in six room-temperature and four refrigerated samples. A majority shift in diagnosis to aCLL (modified Matutes: n = 8/10; adapted Matutes: n = 7/10) was observed at 96 h for refrigerated samples. Conclusion: These findings indicate that pre-analytical variables influence antigen stability in CLL samples, with better preservation at refrigerator temperature, recommending analysis within 48 h of collection. What this study adds: This study highlights the impact of pre-analytical variables on the flow cytometric diagnosis of CLL. Extended room temperature storage alters antigen expression, shifting Matutes scores and potentially affecting the final diagnosis. The findings emphasise optimised sample handling, for improved diagnostic accuracy in laboratory medicine.
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spelling doaj-art-a0127e662dcf461da1e2f8048930fc6d2025-08-20T02:05:28ZengAOSISAfrican Journal of Laboratory Medicine2225-20022225-20102025-05-01141e1e810.4102/ajlm.v14i1.2688502Effects of sample age and storage temperature on the flow cytometric diagnosis of chronic lymphocytic leukaemia in South AfricaShaun M. Grobler0Anne-Cecilia van Marle1Department of Haematology and Cell Biology, Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa; and Department of Haematology, National Health Laboratory Service, BloemfonteinDepartment of Haematology and Cell Biology, Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa; and Department of Haematology, National Health Laboratory Service, BloemfonteinBackground: Chronic lymphocytic leukaemia (CLL) is a haematological neoplasm with characteristic flow cytometric immunophenotyping. Pre-analytical variables impact the quality and reproducibility of flow cytometric data, which could alter the diagnosis from CLL to atypical CLL (aCLL). Objective: This study investigated the effects of pre-analytical variables, specifically sample age and storage temperature, on the stability of key antigens used in the diagnosis of CLL. Methods: Serial flow cytometric analyses were performed from January 2022 to March 2023 on blood samples of 10 CLL patients from the Universitas Academic Hospital Haematology Clinic in Bloemfontein, South Africa. Samples were stored at room and refrigerator temperatures and analysed at baseline, 24 h, 48 h, 72 h and 96 h. We recorded the percentage and intensity of antigen expression of CLL makers, including CD5, CD20, CD23, CD79b, CD200 and sIgM, and assessed whether these affected the adapted and modified Matutes scores. Results: Statistically significant changes were observed in CD5 (p = 0.028), CD23 (p = 0.003) and CD200 (p = 0.005) expression, with better stability at refrigerator temperature. Two samples showed changes in both Matutes scores by 24 h, irrespective of storage temperature. By 48 h, scores changed to aCLL in six room-temperature and four refrigerated samples. A majority shift in diagnosis to aCLL (modified Matutes: n = 8/10; adapted Matutes: n = 7/10) was observed at 96 h for refrigerated samples. Conclusion: These findings indicate that pre-analytical variables influence antigen stability in CLL samples, with better preservation at refrigerator temperature, recommending analysis within 48 h of collection. What this study adds: This study highlights the impact of pre-analytical variables on the flow cytometric diagnosis of CLL. Extended room temperature storage alters antigen expression, shifting Matutes scores and potentially affecting the final diagnosis. The findings emphasise optimised sample handling, for improved diagnostic accuracy in laboratory medicine.https://ajlmonline.org/index.php/ajlm/article/view/2688chronic lymphocytic leukaemiaatypical chronic lymphocytic leukaemiaflow cytometrymatutes scorepre-analytical variablesstorage timestorage temperature
spellingShingle Shaun M. Grobler
Anne-Cecilia van Marle
Effects of sample age and storage temperature on the flow cytometric diagnosis of chronic lymphocytic leukaemia in South Africa
African Journal of Laboratory Medicine
chronic lymphocytic leukaemia
atypical chronic lymphocytic leukaemia
flow cytometry
matutes score
pre-analytical variables
storage time
storage temperature
title Effects of sample age and storage temperature on the flow cytometric diagnosis of chronic lymphocytic leukaemia in South Africa
title_full Effects of sample age and storage temperature on the flow cytometric diagnosis of chronic lymphocytic leukaemia in South Africa
title_fullStr Effects of sample age and storage temperature on the flow cytometric diagnosis of chronic lymphocytic leukaemia in South Africa
title_full_unstemmed Effects of sample age and storage temperature on the flow cytometric diagnosis of chronic lymphocytic leukaemia in South Africa
title_short Effects of sample age and storage temperature on the flow cytometric diagnosis of chronic lymphocytic leukaemia in South Africa
title_sort effects of sample age and storage temperature on the flow cytometric diagnosis of chronic lymphocytic leukaemia in south africa
topic chronic lymphocytic leukaemia
atypical chronic lymphocytic leukaemia
flow cytometry
matutes score
pre-analytical variables
storage time
storage temperature
url https://ajlmonline.org/index.php/ajlm/article/view/2688
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