From the Research
The International Normalized Ratio (INR) of a unit of fresh frozen plasma (FFP) is approximately 1.0 to 1.2. This is because FFP is derived from the plasma of healthy donors with normal coagulation profiles. FFP contains all the coagulation factors at normal physiological levels, which is why it has an INR close to the normal range. When FFP is transfused to patients with elevated INR due to coagulation factor deficiencies, it helps normalize their coagulation status by replacing the missing factors. Each unit of FFP (about 200-250 mL) typically raises coagulation factor levels by approximately 10-20% in an average-sized adult. For clinical effectiveness in correcting coagulopathy, the typical dose is 10-15 mL/kg body weight, often requiring multiple units. The effect of FFP is temporary, lasting about 6-8 hours, as the transfused coagulation factors have limited half-lives in circulation. The change in INR per unit of FFP transfused can be predicted by the pretransfusion INR, as shown in a study published in the American Journal of Clinical Pathology 1. However, the use of FFP alone may not be sufficient to correct coagulopathy in all patients, and the addition of other agents such as prothrombin complex concentrate (PCC) may be necessary in some cases, as demonstrated in studies published in Neurosurgery 2, Pharmacotherapy 3, World Journal of Surgery 4, and The American Surgeon 5. In general, the goal of FFP transfusion is to achieve an INR of less than 1.5, which is considered a safe threshold for most surgical procedures. However, the optimal INR target may vary depending on the individual patient and the specific clinical context. Overall, FFP remains an important component of coagulopathy management, and its use should be guided by evidence-based guidelines and individual patient needs.