|
Rather than ordering levels on all the
factors, we can now narrow it down to just four: XII, XI, IX and VIII.
Factor XII and XI deficiencies are pretty
uncommon, so let's start with the most frequent.
- Statistically, von Willebrand's disease
is actually the most common genetic bleeding disorder, but his aPTT is
longer than usually seen with this, and his type of bleeding suggests
something not linked to platelet response.
Let's start with by checking levels in the
proteins unique to the intrinsic system.
- Of these, factor VIII deficiency is most
common, followed by IX. Just playing the odds, we get a level on VIII.
- His factor VIII is 100% of expected.
- Well, these things happen. So we go to
the next most common, factor IX.
- His factor IX is 12% of expected.
|
Click the image for a larger perspective. |