A Study Comparing Factor Level and Inhibitor Titer Testing Results Drawn From Central Venous Lines and Venipuncture

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.

Inclusion Criteria:

- Children and adults with hemophilia A or B, ages 1-21 who have CVLs for factor
infusion and who are prescribed factor prophylaxis for treatment of their bleeding
disorder will be included.

- Subjects will be recruited from active patients at federally funded hemophilia
treatment centers (HTCs).

Exclusion Criteria: