. Author manuscript; available in PMC: 2018 Jul 5.

Published in final edited form as: Haemophilia. 2018 Feb 15;24(2):186–197. doi: 10.1111/hae.13424

TABLE 4. Example of factor VIII (FVIII) inhibitor measurement on a haemophilia A patient specimen containing Hemlibra^® (emicizumab, ACE910) using the Nijmegen-Bethesda assay and the chromogenic Bethesda assay.

	Predilution	Patient Mix U/dL FVIII^a	Control Mix U/dL FVIII^a	% Residual Activity^b	Calculated Units^c	Total Units^d
Nijmegen-Bethesda Assay	Undiluted	116	37	313.5	0 NBU	IS
Chromogenic Bethesda Assay	Undiluted	23	37	62.2	0.69 CBU	0.7 CBU

IS, interfering substance.

Units per decilitre of FVIII activity.

Patient mix units per decilitre FVIII activity/control mix units per decilitre FVIII activity × 100.

Nijmegen-Bethesda units (NBU) or chromogenic Bethesda units (CBU) calculated as NBU or CBU = (2-log %residual activity) (0.301)⁻¹.

Calculated NBU × predilution factor.

TABLE 4. Example of factor VIII (FVIII) inhibitor measurement on a haemophilia A patient specimen containing Hemlibra® (emicizumab, ACE910) using the Nijmegen-Bethesda assay and the chromogenic Bethesda assay.