Patients with hemophilia A and B sometimes require the placement of a central venous line (CVL). A CVL is a medical device that is placed into a vein that gives easier access to a vein either for a blood draw or to give factor replacement product.~Patients with hemophilia are usually seen by the hemophilia doctor every year at the annual comprehensive clinic visit. As part of this visit, the doctor usually orders routine blood tests, including the factor level and inhibitor titer.The factor level and inhibitor blood tests are always taken through a peripheral stick. A peripheral stick means that a small needle is inserted into a vein in order to obtain a blood sample. The CVL is not used for these blood draws. This is because the investigators don't know if the infusion of factor replacement product and heparin (a blood thinning drug used to flush the line after a factor infusion) can cause the blood sample results to be incorrect. The current practice is to take blood through a needle stick in the vein because the investigators can be sure that the results are accurate.~When blood draws are taken through a peripheral stick, it can cause children with hemophilia to be very anxious because of the pain involved with a needle stick. Also, the needle stick can sometimes cause a bleed, which may require treatment.~The purpose of this research study is to see if factor levels and inhibitor levels are accurate when they are drawn from a CVL instead of from a peripheral stick.
The purpose of this research study is to see if factor levels and inhibitor levels in Hemophilia A and B subjects are accurate when they are drawn from a central venous line (CVL) instead of from a peripheral stick.