TABLE 1.

D‐dimer and DDR results of 12 samples on four commercial assays

	D‐dimer value					D‐dimer ratio
	Assay 1 a	Assay 2 b	Assay 3 c	Assay 4 d	Maximum difference e	Assay 1	Assay 2	Assay 3	Assay 4	Maximum difference
ULN	243	0.5	1	0.5
Report unit	ng/mL	mg/L	μg/ml	μg/ml
Express unit	DDU	FEU	DDU	FEU
Sample 1	130	0.32	0.60	0.27	481.5	0.53	0.64	0.6	0.54	1.21
Sample 2	132	0.25	0.96	0.34	528.0	0.54	0.50	0.96	0.68	1.92
Sample 3	153	0.26	0.78	0.37	588.5	0.63	0.52	0.78	0.74	1.50
Sample 4	254	0.64	1.02	0.64	396.9	1.04	1.28	1.02	1.28	1.25
Sample 5	755	2.05	2.87	1.97	383.2	3.11	4.10	2.87	3.94	1.43
Sample 6	967	2.52	3.83	2.55	383.7	3.98	5.04	3.83	5.10	1.33
Sample 7	1030	1.82	3.70	1.59	647.8	4.24	3.64	3.70	3.18	1.33
Sample 8	1525	3.07	5.33	3.34	496.7	6.28	6.14	5.33	6.68	1.25
Sample 9	2091	4.67	5.97	4.01	521.4	8.61	9.34	5.97	8.02	1.56
Sample 10	2772	6.18	7.40	4.97	557.7	11.41	12.36	7.40	9.94	1.67
Sample 11	2891	5.83	8.07	5.94	495.9	11.90	11.66	8.07	11.88	1.47
Sample 12	5095	7.44	13.38	8.01	684.8	20.97	14.88	13.38	16.02	1.57
Total					513.8 ± 97.4					1.46 ± 0.21

Abbreviations: DDU, D‐dimer unit; FEU, fibrinogen equivalent unit; ULN, the upper limit of the normal range.

^a Assay 1, Werfen ACL‐TOP 750 with HemosIL D‐Dimer HS reagent;

^b Assay 2, Sysmex CS5100 with Siemens Innovance D‐dimer reagent;

^c Assay 3, Sekisui CP3000 with Nanopia D‐dimer reagent;

^d Assay 4, Stago STA‐R MAX with STA Liatest D‐Di reagent.

^e Maximum difference means that the maximum value of four results from the same sample divided by the minimum; e.g., Sample 12: 5095 divided by 7.44 is 684.8 for D‐dimer value, and 20.97 divided by 13.38 is 1.57 for D‐dimer ratio.