 Second, the expected improvement in coagulation factor tests following a FP transfusion is often not seen especially in mild to moderate coagulation test abnormalities. Given the concentration of 1 unitml for individual coagulation factor levels in FP, transfusing four units of FP approximately 800-1000 mls to a 70 kg patient with a 5-litre blood volume, would be expected to increase levels by a maximum of 16. However, the effect on the INR will also depend on the starting level of the coagulation factors. If the levels are very low less than 10, this will result in a significant improvement in the INR, but if the initial levels are only mildly decreased, the same increase in coagulation factor levels will make little change in the INR. Furthermore, the INR FP units can be as high as 1.3. The lack of efficacy of FP to correct the INR or aPTT in patients with mild increases in the INR has been demonstrated in a number of studies. 