Table 1.

Pre- and posttest probability of HIT using a combined approach of the 4Ts and EIAs

Reference	Design	N	Pretest probability of 4Ts			Posttest probability of 4Ts (+ assay/− assay)
			Low (0-3)	Intermediate (4-5)	High (6-8)	Low (0-3)	Intermediate (4-5)	High (6-8)
27	Single center, retrospective	1291	0.8%	14%	53%	NR	65%/0%	95%/0%
28	Multicenter, prospective	380	2.1%	11%	47%	11%/0.06%	42%/0.4%	83%/2.6%
24	Multicenter, prospective	526	1.9%	7%	37%	15%/0%	42%/0%	88%/0%

EIA, enzyme immunoassay; NR, not reported.