Assay
for Activated Protein C Resistance
Test used:
aPTT
Patient plasma + aPTT reagent
incubated for 3 minutes
Procedure:
CaCl2 added and timer started
Timer stopped when fibrin strand
forms
1
2
Patient plasma + aPTT reagent + APC
incubated for 3 minutes
CaCl2 added and timer started
Timer stopped when fibrin strand
forms
Interpretation:
Normal = when 2 is ½ length of time of 1
APC resistance = when 2 is lengthened so ratio of 2:1 is shortened
