PT/PTT Mixing Study Reflex Testing / gyg

PT/PTT Mixing Study Reflex Testing / gyg

Department of Pathology and Laboratory Medicine
IU Health Pathology Laboratory
Indianapolis, IN 46202
PT/PTT
Mixing
/
g Studyy Reflex Testing
g
Before proceeding, rule out heparin with TCT
Prolonged PT
Normal PTT
PT=13.0-14.9s
VII Only (no mix)
Low VII
Stop
Normal VII
FII, V, X
Normal PT
Prolonged PTT
PT>14.9s
PTT=38.1-41.0s
Mix (no incubation)
+ VII
Stop
Normal VII
FII, V, X
DRVVT/SCT only
(no mix)
FVIII, IX,
XI
XI, XII
Factor XII
Stop
Incubated mix
Fibrinogen
Mix with incubation
No Correction
Normal DRVVT/SCT
Low XII
Prolonged PT
Prolonged PTT
Rule out
heparin
PTT>41.0s
Corrects
Low VII
Normal PT/PTT
Prolonged TCT
Normal XII
Clinical Presentation
DRVVT/SCT
Normal
Low
Lo
Stop
Fibrinogen
Antigen
Specific
Factor
Inhibitor
FVIII, IX, XI
Corrects
Factors II, V, X
Any Low
Stop
Normal
II,, V,, X
Fibrinogen
Normal
Stop
Low
Fibrinogen
Antigen