06-28-2010, 09:35 AM
What does an elevated LA-PTT indicate?
06-29-2010, 11:15 AM
I must be having a serious case of brain fog because I could have sworn that I did some research on this question for you before....uggh. Sorry :-(
Anyway, PTT means
"Partial Thromboplastin Time"
the PTT test is ordered when someone has unexplained bleeding or clotting and/or
to monitor heparin anticoagulant therapy. Heparin is a drug that is given intravenously (IV) or by injection to prevent and to treat blood clotting.
It may also be ordered, along with other tests when a patient has unexplained bleeding or bruising, or thromboembolism or when a chronic condition (such as Lupus) is suspected.
A Normal PTTs may reflect normal clotting function. If the lupus anticoagulant (LA) is suspected, an LA-sensitive PTT is used to test for it.
A decreased PTT may result when coagulation factor VIII is elevated. This may occur during an acute phase reaction, a condition causing acute tissue inflammation or trauma (such as Lupus).
A decreased PTT may result when coagulation factor VIII is elevated.
There may be a coagulation factor deficiency or a specific or nonspecific inhibitor affecting the body’s clotting ability.
Inhibitors may be antibodies that specifically target certain coagulation factors, such as Factor VIII antibodies, or they may be non-specific inhibitors, such as lupus antocoagulant and anticardiolipin antibodies that bind to chemicals called phospholipids found on the surface of platelets.
If there is LA or Anticardiolipin, then doctors who suspect Lupus may run other tests in order to confirm the diagnosis. It is one, of many, tests used to narrow down a diagnosis.
The results of each of the lupus anticoagulant tests either lead towards or away from the likelihood of having a lupus anticoagulant. Although the tests done may vary, they usually begin with a prolonged PTT:
If the PTT or LA-PTT is prolonged, and mixing it with normal pooled plasma does not “correct” the result, then it is likely that there is an inhibitor present. If the prolonged test corrects when phospholipid is added, then it is likely that a lupus anticoagulant is present. (After heparin contamination, a lupus anticoagulant is the most common reason for a prolonged PTT).
If the PTT is not prolonged, there may not be a lupus anticoagulant present, the test reagents may contain too much phospholipid, or the test may not be sensitive enough to pick up the lupus anticoagulant. The LA sensitive PTT may need to be done.
If a dRVVT or MRVVT test is prolonged and does not correct when mixed with normal pooled plasma but does correct with the addition of phospholipids, then it is likely that a phospholipid antibody is present.
I hope that this has been helpful to you and answered your questions. :-)
Peace and Blessings
07-07-2010, 09:41 PM
Sorry for my delay in thanking you for the response, but we just got our DSL back up again. I appreciate your taking the time to post this.