All the patients in that study were examined within the first 24 h after the onset of symptoms. In another study, only two of 18 patients with PE had a normal pFPA level; however, both patients were examined more than five days after the onset of symptoms. These findings suggest that FPA generation may normalize in patients examined more than 24 h after the onset of symptoms. Furthermore, the inverse relationship of symptom duration (time elapsed between the onset of symptoms and the examination) and the pFPA concentration was elegantly demonstrated by Yudelman et al. All of the patients with PE whose cases were reported in this study were examined within 24 h after the onset of symptoms. ventolin 100 mcg
Thus, it is not surprising that our finding of 100 percent sensitivity is in agreement with that of van Hulsteijn et al. Therefore, we believe that our results should not be extended to patients who are seen with prolonged symptom duration or chronic PE. As in other studies,”‘ we found elevated pFPA concentrations in some patients who have a relatively increased rate of fibrin generation for a variety of reasons other than PE. The high specificity of the uFPA test for PE reported in this study (82 percent), as well as that reported for pFPA,* is probably enhanced by patient selection bias. For example, most of the patients with conditions other than PE that could elevate uFPA were excluded prospectively.