From Joyce Low: We have a patient with a prolonged prothrombin time (PT) and normal partial thromboplastin time (APTT, PTT). He bled, but factor levels were all normal. He’s an 84 year old man here for pacemaker insertion. PT was 19s (Neoplastine; reference interval 11–15s ), PTT 31s (Actin FS RI 25–35s), thrombin time, fibrinogen, and platelets normal. Patient developed a hematoma and infection at pacemaker insertion site. Pacemaker subsequently removed with bleeding that required 3 fresh frozen plasma twice.
From Lorna Bogertman, Valley Health: Hello George, I have a question concerning lupus anticoagulant (LA) testing. We have had several requests from physicians to perform hexagonal phase LA testing only. Is it valid to perform this test without the rest of the LA profile? We have found that if we performed Stago’s LA-sensitive partial thromboplastin time (PTT-LA) and the dilute Russell viper venom time (DRVVT), the LA would have been reported as negative, however in this case the hex phase test was positive. How should this be reported? If the profile is really negative, what are the other causes of a positive hex phase test other than LA?
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From Dr. Jeanine Walenga, Loyola University Medical Center: George, what could be the reason(s) for a 30 yo female patient having multiple
mild factor deficiencies of FIX (64%) and FXII (51%)? The activated partial thromboplastin time (APTT, PTT) was slightly prolonged but corrected with a mixing study. FVIII and FXI were normal. Patient does not have LA or anti-phospholipid antibodies. The best I came up with was that the deficiencies might be due to enhanced excretion from a nephrotic syndrome. Would the double factor deficiencies account for the slightly prolonged APTT? Does the patient have a bleeding risk if going for surgery? Thanks.
This was posted by a colleague on another forum. We have noticed that newborn babies plasma, after three weeks on extracorporeal membrane oxygenation (ECMO) becomes dark brown. On our instrument, the fibrinogen rises to approximately 800 mg/dL, though a reference lab reports it as critically low. We also notice falsely elevated platelet counts, for instance, 150,000 by impedance and 50,000 by optical, but the manual estimate is 15,000. The manufacturer says the fibrinogen could cause a falsely elevated platelet count. Could there be a common denominator causing these interferences?
As anticipated, Ben Troyer’s August 31, 2014 question about STAT lupus anticoagulant testing drew a number of comments. George also discussed the question with local colleagues who brought up the rare possibility of catastrophic antiphospholipid syndrome (CAPS, Asherson Syndrome), see attached article for description. This may be an additional reason for ordering a STAT LA test, however we agreed it is not a reason for listing LA as a STAT procedure.