Overview
Patients receiving replacement of coagulation factors should have the levels of factors measured before and after the infusion. If the actual increment in factor levels after transfusion is much less than the expected increment, then antibodies or increased consumption may be present.
Procedure
(1) Measure the real increment in factor activity achieved, by subtracting pre-transfusion factor levels from post-transfusion factor levels. The post-transfusion specimen is should be collected soon after distribution is complete.
(2) Calculate the increment expected based on amount of factor given. The actual in vivo recovery seen varies for each factor
estimated increment if 100% recovery =
= ((units of factor activity per replacement product) * (number of products given) / (plasma volume))
|
|
Half-Life |
in vivo recovery |
|
Factor 1 |
3 - 6 day |
50 - 70% |
|
Factor 2 |
50 - 80 hours |
50% |
|
Factor 5 |
4.5 - 36 hours |
80% |
|
Factor 7 |
2 - 5 hours |
100% |
|
Factor 8, anticoagulant |
8 - 12 hours |
60 - 70% |
|
Factor 8, von Willebrand's |
24 hours |
|
|
Factor 9 |
18 - 24 hours |
20% |
|
Factor 10 |
20 - 42 hours |
50 - 95% |
|
Factor 11 |
40 - 80 hours |
90% |
|
Factor 12 |
50 hours |
|
|
Factor 13 |
7 - 14 days |
50 - 100% |
(3) If the real increment is much less than the expected, then work the patient up for causes of failure to achieve acceptable levels, starting with anti-factor antibodies and DIC.
Specialty: Hematology Oncology, Clinical Laboratory, Clinical Laboratory, Pharmacology, clinical
