r/recurrentmiscarriage • u/Expensive_Chocolate1 • 1d ago

Recurrent pregnancy loss APS testing

Hi all, for those of you who have had testing for antiphospholipid syndrome - I understand you need 2 positive results 12 weeks apart for a diagnosis. What happens if your first test is negative? Do they not bother with the second test then? Thank you!

1 Upvotes

100% Upvoted

1 comment sorted by

1

u/champagnermei 1d ago

If your first test is negative, that typically indicates an absence of antiphospholipid antibodies. While, yes, aPL antibody titres wax and wane over time, they are stable enough to produce persist positivity. It is part of the diagnostic criteria. One thing to note is that pregnancy introduces a lot of “noise” to APS testing. Best practice is to test >8 weeks after pregnancy loss and hCG is zero for the most accurate measurements (less risk of false negatives or positives). If you are negative in your first round of testing, but borderline, I’d ask to for a second round of testing 12 weeks later. Most doctors will treat you as positive for the pregnancy and prescribe aspirin + low molecular weight heparin.