Table 2.

Effect of increased level of factor VIII on the second-derivative curve in the activated partial thromboplastin time assay in plasma derived from patients with acquired von Willebrand disease or hemophilia A

Added concentration of FVIII (FC; IU/ml)	Patients
	Patient with acquired vWD				Patient with hemophilia A
vWF:Ag (%)	FVIII:C (%)	APTT (s)	Type of curve	vWF:Ag (%)	FVIII:C (%)	APTT (s)	Type of curve
0.0	7.1	6.7	45.2	ABN-B	147.5	7.5	45.1	ABN-S
0.1	7.4	18.9	38.2	ABN-S	142.8	17.8	39.7	ABN-S
0.2	6.6	30.0	36.0	ABN-S	112.3	27.9	38.3	ABN-S
0.3	6.8	41.8	35.5	ABN-S	108.6	36.6	37.5	ABN-S
0.4	7.6	57.8	34.9	ABN-S	104.5	48.5	36.8	N
0.5	5.9	68.4	34.6	ABN-S	98.3	57.3	36.2	N

Factor VIII concentrate was added to the plasma derived from patients with acquired von Willebrand disease (vWD) or hemophilia A. The level of factor VIII (FVIII) was increased by FVIII concentrates in both patients’ plasmas, but the abnormal curve was not disappeared only in plasma derived from a patient with acquired vWD. Type of curve indicates the status of the second-derivative curve in the activated partial thromboplastin time assay. N, normal; ABN-B, abnormal, biphasic-type; APTT, activated partial thromboplastin time; ABN-S, abnormal, shoulder-type; FC, vWF, and FVIII:C, final concentration, antigen level of von Willebrand factor, and factor VIII activity, respectively. Supplementary data.