Factor
V, II, VII, or X assay
Specimen requirements:
Fresh whole blood collected in
sodium citrate at a 9:1 ratio of blood to anticoagulant
Principle:
The aPTT test is used to determine
if normal or abnormal levels of these factors are present.
If there is a factor deficiency it
is identified using substitution testing
Once factor is identified the level
of factor present in patient sample can be quantitated using factor deficient plasma with varying dilutions of
patient plasma and determining the % correction that occurs in the aPTT
Tested within 2 hours or stored at
-20oC for 2 – 5 days