A randomized and blinded comparison of the sensitivity and the reproducibility of the Ivy and Simplate II bleeding time techniques.

The authors compared the sensitivity and the reproducibility of the bleeding time techniques according to Ivy and Simplate II. The sensitivity was studied in two groups: one group of 64 healthy volunteers and another group of 40 patients with various disorders of hemostasis, including 28 patients with Von Willebrand's disease. Ivy and Simplate II bleeding times were performed on each subject. The reproducibility was studied in 48 patients with mildly or moderately prolonged bleeding times that resulted from various disorders who had a duplicate Ivy or a duplicate Simplate II bleeding time. All subjects were randomized over the technologists and they were blinded for each other's results. By a receiver operating characteristic analysis, the Ivy method appeared to offer greater overall detection efficacy than the Simplate II method. For the Ivy method, the standard deviation of the ratios of the duplicate bleeding times was 0.37 and for the Simplate II method it was 0.33. The authors conclude that the Simplate II method is not superior in sensitivity or reproducibility to the Ivy method, which is cheaper, takes less time, and does not leave scars.