Prolonged APTT but negative Lupus anticoagulant

[Christinoula]

Is it normal for patients with APS, but negative Lupus anticoagulant, to have slightly prolonged APTT 42.2 sec (normal range: 25.9-36.6 sec) with normal INR 1.10;

[Star13]

This link may explain it better, in particular where its says:

Mixing tests introduce a dilution factor and may lead to a false negative LA result. Samples that generate a negative result on mixing but have a prolonged APTT-based test and/or dRVVT and a positive confirmatory tests should be considered positive for the presence of a LA. Alternative mix ratios e.g. 4:1 patient plasma:normal pooled plasma may be used if validated by the laboratory.

practical-haemostasis.com/T...

[Christinoula in reply to Star13]

Thank you for the link! I' ll study it and discuss the issues with my dr. I hope I will be able to understand the details, as English is not my mother language.

[MaryF Administrator in reply to Christinoula]

I hope your doctor finds this paper useful, let us know their opinion. MaryF

[Lure2 in reply to Star13]

Hi Star13,

I wonder if you are a Medical Doctor as to the link you send. A bit difficult to understand for us perhaps? Do you have APS yourself?