Lab CE Course - Coagulation Inhibitors and Factor Deficiencies
40%
MINIMUM percentage of each coagulation factor present in a patient's plasma to produce a normal PT and aPTT
Factor deficiencies and coagulation inhibitors that prolong a PT and/or aPTT test result
Mixing studies may help to determine the presence of
1:1
Ratio of patient plasma to pooled normal plasma used in a mixing study
4 hours
A mixing study should be performed within what time frame following collection of the specimen?
True
A thrombin time will detect heparin in a patient's plasma so that heparin does not produce a false-positive aPTT mixing study result.
Anti-factor VIII inhibitor
ACQUIRED hemophilia A may be the result of which of the following conditions
slow-acting inhibitor
Both anti-factor VIII and lupus anticoagulant have been known to be
Collecting a specimen for aPTT testing from a heparinized vascular access device
Falsely prolonged aPTT test result
Corrected, Factor Deficiency
Initial PT: 23 sec Immediate Mixing Study PT: 12 sec Incubated Mixing Study PT: 13 sec Corrected or not-corrected? Factor deficiency or coagulation inhibitor?
Increased platelets in plasma sample
What may prevent the detection of lupus anticoagulant in a plasma sample if the blood used for testing is not centrifuged for a sufficient time?
You have not run a PT or aPTT on the new mix before incubating
When performing your mixing study, you aliquot your sample plasma and the pooled normal plasma to create your "mix". You then place the mix in a water bath to incubate for 90 minutes before testing your new mixed sample. What is the problem with the steps involved in the procedure above?
A pooled plasma from at least 20 healthy donors having normal PT/aPTT results
acceptable as the "normal" plasma reagent to use in a mixing study
Check for clots in the sample Check patient history Check for anticoagulant therapy
investigation of an initially prolonged PT test
II
may be deficient if both the PT and aPTT are prolonged
Lupus anticoagulant (anti-phospholipid antibody)
most common coagulation inhibitors
VII
prolongation of the PT test if the aPTT test is normal
Bethesda assay
quantify a coagulation inhibitor