Variability in combinations of APTT reagent and substrate plasma for a one-stage clotting assay to measure factor VIII products

Atsuo Suzuki; Nobuaki Suzuki; Takeshi Kanematsu; Shuichi Okamoto; Naruko Suzuki; Shogo Tamura; Ryosuke Kikuchi; Akira Katsumi; Tetsuhito Kojima; Tadashi Matsushita

doi:10.1111/ijlh.14258

Variability in combinations of APTT reagent and substrate plasma for a one-stage clotting assay to measure factor VIII products

Int J Lab Hematol. 2024 Mar 1. doi: 10.1111/ijlh.14258. Online ahead of print.

Authors

Atsuo Suzuki¹, Nobuaki Suzuki², Takeshi Kanematsu³, Shuichi Okamoto⁴, Naruko Suzuki⁵, Shogo Tamura⁶, Ryosuke Kikuchi⁷, Akira Katsumi⁸, Tetsuhito Kojima^{4

9}, Tadashi Matsushita^{2

3}

Affiliations

¹ Department of Medical Technique, Nagoya University Hospital, Nagoya, Japan.
² Department of Transfusion Medicine, Nagoya University Hospital, Nagoya, Japan.
³ Department of Clinical Laboratory, Nagoya University Hospital, Nagoya, Japan.
⁴ Division of Cellular and Genetic Sciences, Department of Integrated Health Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan.
⁵ Department of Haematology-Oncology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
⁶ Graduate School of Health Sciences, Hokkaido University, Sapporo, Japan.
⁷ Division of Clinical Laboratory, Gifu University Hospital, Gifu, Japan.
⁸ Department of Haematology, National Centre for Geriatrics and Gerontology, Obu, Japan.
⁹ Aichi Health Promotion Foundation, Nagoya, Japan.

PMID: 38426662
DOI: 10.1111/ijlh.14258

Abstract

Introduction: An investigation of the suitability of reagents for measuring FVIII products in a one-stage clotting assay (OSA) showed variations in their FVIII activity (FVIII:C). Most studies have focused on the activated partial thromboplastin time (APTT) reagent rather than FVIII-deficient plasma (F8DP), even though the APTT-based OSA is comprised of APTT reagents and factor-deficient plasma.

Aim: A single-centre study was conducted to clarify variations in measurements of FVIII products in an OSA using a total of 12 reagent combinations, including four APTT reagents and three types of F8DP.

Methods: FVIII:C in nine types of FVIII product-spiked plasma was measured using an OSA with four different APTT reagents and three types of F8DP.

Results: F8DP-dependent variations were found in addition to differences derived from APTT reagents. Variations in target recovery (TR) were observed for NovoEight®, Eloctate®, and Jivi®. Reduced TR for Jivi was found only for Pathromtin SL in combination with congenital F8DP (F8DP-3). This lower TR was not observed with alternative manufacturing lots of F8DP-3. The reduced TR for Jivi might be related to impaired contact activation due to lower factor XI activity in F8DP-3.

Conclusion: In addition to APTT reagents, variations in F8DPs used for OSAs can also affect FVIII:C results. F8DPs as well as the APTT reagent used for OSA should be chosen with caution, and laboratories should evaluate reagents for F8DPs as they currently do for APTT reagents, especially when lot changes occur.

Keywords: FVIII-deficient plasma; factor VIII; one-stage clotting assay.

Abstract

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