Deficient factor in case of prolonged PT and PTT result that corrected with the addition of normal pooled plasma. All other screening tests are normal. I think it is factor V. Can you suggest that it is right?
Hello, and thank you for your question. Assuming the patient is not on heparin or coumadin, and does not have liver disease or vitamin K deficiency, a prolong prothrombin time (PT) and partial thromboplastin time (PTT) that are corrected upon an immediate and incubated mixing study indicate a possible single factor deficiency of either prothrombin (factor II), factor V (as you suggest), or factor X. Be sure you perform both the immediate and incubated mixing study to confirm there is no inhibitor present.
This combination of results could also indicate a severe fibrinogen deficiency, however the PT and PTT only prolong when fibrinogen is below 100 mg/dL. Most prefer to perform the fibrinogen assay to confirm fibrinogen level. For more information, please see my audio module #25, Mixing Studies. I hope this helps. Geo