Table 2.

Early D-dimer trends and associations with VTE.

A. Changes in D-dimer pre-VTE and association with VTE (N = 80)
1. Variable: Ceiling D-dimer (ng/mL) (pre-VTE or d10-14)
Threshold	Sensitivity	Specificity	PPV	NPV
1500	92	21.8	34.8	85.7
2000	80	32.7	35.1	78.2
3000	72	47.3	38.3	78.8
4000	72	58.2	43.9	82.1
5000	68	70.9	51.5	83
2. Variable: Delta D-dimer (ng/mL)
Threshold	Sensitivity	Specificity	PPV	NPV
100	96	32.7	39.3	94.7
250	92	34.5	39	90.5
500	84	40	38.9	84.6
1000	76	50.9	41.3	82.3
1500	64	56.4	40	77.5
2500	64	67.3	47.1	80.4
4500	96	32.7	56.8	79
3. Variable: Rate of D-dimer rise (delta d-dimer/d)
Threshold	Sensitivity	Specificity	PPV	NPV
90	84	50.9	44.5	87.5
150	72	61.8	46.1	82.9
300	60	74.5	51.7	80.4
500	56	83.6	60.1	80.7
B. D-dimer trends within the first 7 d of hospitalization and association with VTE (N = 78)
1. Variable: D-dimer (ng/mL) max d1–7
Threshold	Sensitivity	Specificity	PPV	NPV
1500	95	37.9	34.5	95.7
2000	75	53.4	35.7	86.1
2500	75	62.1	40.6	87.8
3000	70	63.8	40	86.1
4000	60	65.5	37.5	82.6
5000	55	69	38	81.6
2. Variable: D-dimer slope (ng/mL/d) d1–7
Threshold	Sensitivity	Specificity	PPV	NPV
100	85	50	37	90.6
150	85	60	42.3	92.1
200	70	66	41.5	86.5
300	50	74	40	81.1
1000	45	83	47.7	81.4